Electric motor and power tool

Abstract

The application relates to a motor and electric tool, which comprises a gear box and a prime mover arranged axially with the gear box. The prime mover comprises a motor cover, a motor assembly and a support. The motor assembly is arranged in the motor cover, and the motor assembly comprises a stator core fixed in the motor cover; the support is arranged axially between the motor assembly and the gear box, a first axial positioning structure is arranged between the support and the stator core, and a second axial positioning structure is arranged between the support and the shell of the gear box. Through the first axial positioning structure, the installation precision of the support and the stator core can be ensured, so that the coaxial degree of the support and the motor cover is high. Through the second axial positioning structure, the installation precision of the support and the gear box can be ensured, so that the coaxial precision of the support and the gear box is high, and finally the coaxial degree between the motor cover and the gear box is high. In the operation process of the motor and the electric tool, vibration is small, large sparks are not easy to generate, damage is not easy to occur, and the service life is long.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of electric machines, in particular to an electric machine and a power tool. BACKGROUND

[0002] An electric machine is a common driving device, which realizes the rotation of an output shaft through the cooperation of a stator and a rotor, and then realizes the transmission of power. In the related art, when an electric machine cover and a gear box are assembled, the two are positioned through two bearings sleeved on the output shaft, and then connected through a locking piece. However, in this connection mode, the electric machine is prone to damage and has a short service life due to large vibration during operation. SUMMARY

[0003] Therefore, it is necessary to provide an electric machine and a power tool to solve the problem that the electric machine in the prior art is prone to damage and has a short service life due to large vibration during operation.

[0004] An electric machine comprises:

[0005] a gear box;

[0006] a prime mover arranged axially with the gear box;

[0007] the prime mover comprises:

[0008] an electric machine cover; and

[0009] an electric machine assembly arranged in the electric machine cover, the electric machine assembly comprising a stator core fixed in the electric machine cover; and

[0010] a support arranged axially between the electric machine assembly and the gear box, the support and the stator core being provided with a first axial positioning structure, and the support and a housing of the gear box being provided with a second axial positioning structure.

[0011] In one of the embodiments, the first axial positioning structure comprises a first positioning column and a first positioning hole which are one-to-one corresponding and cooperated with each other to position the support and the stator core in the axial direction.

[0012] In one of the embodiments, the first positioning hole is arranged on a side of the stator core axially facing the support;

[0013] the first positioning column is arranged on a side of the support axially facing the stator core.

[0014] In one of the embodiments, the first positioning column and the first positioning hole are clearance fitted;

[0015] and the clearance d1 between the first positioning column and the first positioning hole satisfies the condition:

[0016] 0.05mm≤d1≤0.15mm.

[0017] In one of the embodiments, the first axial positioning structure comprises at least one set of first positioning posts.

[0018] Each of the first positioning post set comprises two first positioning posts in diametrically opposite positions.

[0019] In one of the embodiments, the bracket further comprises a positioning protrusion on the side close to the stator core in the axial direction.

[0020] When the first positioning post cooperates with the first positioning hole, the positioning protrusion abuts against the stator core.

[0021] In one of the embodiments, the height h of the positioning protrusion in the axial direction satisfies the condition:

[0022] 0.1mm≤h≤0.3mm.

[0023] In one of the embodiments, the second axial positioning structure comprises second positioning posts and second positioning holes which are in one-to-one correspondence and cooperate with each other to position the bracket and the gear box housing in the axial direction.

[0024] In one of the embodiments, the second positioning post is arranged on the side of the bracket facing the gear box housing in the axial direction; the second positioning hole is arranged on the side of the gear box facing the bracket in the axial direction; or

[0025] The second positioning post is arranged on the side of the gear box facing the bracket in the axial direction; the second positioning hole is arranged on the side of the bracket facing the gear box housing in the axial direction.

[0026] In one of the embodiments, the second positioning post and the second positioning hole are clearance fit.

[0027] The clearance d2 between the second positioning post and the second positioning hole satisfies the condition:

[0028] 0.05mm≤d2≤0.15mm.

[0029] In one of the embodiments, the stator core and the motor cover are provided with a third axial positioning structure.

[0030] In one of the embodiments, the third axial positioning structure comprises third positioning posts and third positioning holes which are in one-to-one correspondence and cooperate with each other to position the motor cover and the stator core in the axial direction.

[0031] In one of the embodiments, the third positioning column is arranged on the side of the motor cover axially close to the stator core; and the third positioning hole is arranged on the side of the stator core axially away from the support.

[0032] In one of the embodiments, the third positioning column and the third positioning hole are in clearance fit;

[0033] and the clearance d3 between the third positioning column and the third positioning hole satisfies the condition:

[0034] 0.05mm≤d3≤0.15mm.

[0035] In one of the embodiments, the motor assembly further comprises a rotating connecting component and a rotor core mounted on the rotating connecting component;

[0036] The stator core is configured to be arranged around the rotor core with a clearance therebetween, and the motor assembly is connected to the gear box through the rotating connecting component for inputting power to the gear box.

[0037] In one of the embodiments, the prime mover further comprises an upper bearing and a lower bearing;

[0038] The upper bearing is sleeved on one end of the rotating connecting component and connected to the motor cover;

[0039] The lower bearing is sleeved on the other end of the rotating connecting component and connected to the gear box;

[0040] The rotor core is located between the upper bearing and the lower bearing.

[0041] In one of the embodiments, the prime mover further comprises a fan, the fan is arranged between the support and the lower bearing, the fan is sleeved on the rotating connecting component and fixedly connected to the rotating connecting component, and the fan can at least partially extend into the support;

[0042] The motor cover, the support and the fan can collectively form an air flow passage.

[0043] In one of the embodiments, the motor cover is further provided with an air inlet and an air outlet;

[0044] When the fan rotates around the rotation axis of the rotating connecting component, air flow can flow into the air flow passage through the air inlet and flow out through the air outlet.

[0045] In one of the embodiments, the air inlet and the air outlet are arranged at opposite ends of the motor cover in the axial direction.

[0046] In one of the embodiments, the bracket is configured with a mounting hole;

[0047] The fan comprises a mounting base and a plurality of blades arranged circumferentially on the mounting base at intervals; each of the blades comprises a first stepped blade and a second stepped blade distributed in a stepped manner from the inside to the outside in the radial direction of the mounting base;

[0048] The first stepped blade is capable of extending into the mounting hole, and the second stepped blade is arranged opposite to the end surface of the bracket away from the stator core.

[0049] In one of the embodiments, the first stepped blade and the second stepped blade are configured as an integral structure.

[0050] In one of the embodiments, the mounting base is arranged to be inclined from the inside to the outside in the radial direction of the mounting base towards one side of the gearbox.

[0051] In one of the embodiments, the bracket is accommodated in the motor cover and is in clearance fit with the motor cover.

[0052] The minimum clearance d4 between the bracket and the motor cover satisfies the condition:

[0053] 0.1mm≤d4≤0.3mm.

[0054] The present application also provides an electric power tool capable of solving at least one of the above technical problems.

[0055] The electric power tool provided by the present application comprises the electric motor described above.

[0056] In one of the embodiments, the electric power tool further comprises a cutting blade.

[0057] The cutting blade is connected with the electric motor.

[0058] The present application has the following beneficial effects:

[0059] This invention provides a motor and power tool. During assembly, the motor assembly is first placed inside a motor housing, and the stator core of the motor assembly is fixedly connected to the motor housing. Then, a first axial positioning structure connects the bracket to the stator core fixedly connected to the motor housing axially. A second axial positioning structure connects the bracket to the gearbox housing, thus achieving the assembly of the motor housing and gearbox. During this assembly process, the first axial positioning structure ensures the installation accuracy of the bracket and stator core, and the fixed connection between the stator core and the motor housing results in high coaxiality between the bracket and the motor housing. The second axial positioning structure ensures the installation accuracy of the bracket and gearbox, resulting in high coaxiality between the bracket and the gearbox, ultimately leading to high coaxiality between the motor housing and the gearbox. During operation, the output shaft connected to the motor housing and gearbox experiences less vibration and is less prone to generating large sparks, thus reducing the risk of damage to the entire motor and extending its service life. Attached Figure Description

[0060] Figure 1 A schematic diagram of a motor provided according to an embodiment of the present invention;

[0061] Figure 2 for Figure 1 An exploded view of some parts of the motor shown;

[0062] Figure 3 for Figure 2 The first schematic diagram of the motor bracket shown;

[0063] Figure 4 for Figure 2 A second schematic diagram of the motor bracket shown;

[0064] Figure 5 for Figure 2 A schematic diagram of the fan of the motor shown;

[0065] Figure 6 for Figure 5 A top view of the fan of the motor shown;

[0066] Figure 7 for Figure 6 The fan of the motor shown is a cross-sectional view along section AA;

[0067] Figure 8 for Figure 1 The diagram shown is a schematic of the internal structure of the motor.

[0068] Figure 9 for Figure 8 A magnified view of part B of the motor shown;

[0069] Figure 10 for Figure 1Second schematic view of the internal structure of the motor shown;

[0070] Figure 11 For Figure 10 Partial enlarged view of the motor shown at C;

[0071] Figure 12 For Figure 10 Partial enlarged view of the motor shown at D;

[0072] Figure 13 For Figure 1 Third schematic view of the internal structure of the motor shown;

[0073] Figure 14 For Figure 13 Partial enlarged view of the motor shown at E.

[0074] Fig. 100 - gear box; 110 - second positioning hole; 200 - motor cover; 210 - first mounting cavity; 220 - third positioning column; 230 - air inlet; 240 - air outlet; 300 - motor assembly; 310 - stator core; 311 - first positioning hole; 312 - third positioning hole; 320 - rotor core; 330 - rotating connecting part; 340 - stator winding; 400 - bracket; 410 - first positioning column; 420 - second positioning column; 430 - positioning block; 440 - mounting hole; 500 - fan; 510 - mounting base; 520 - blade; 521 - first stepped blade; 522 - second stepped blade; 610 - upper bearing; 620 - lower bearing; 710 - first connecting piece; 720 - second connecting piece. DETAILED DESCRIPTION

[0075] In order to make the above objectives, features and advantages of the present application more apparent, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without some or all of these specific details. In other instances, well known process steps have not been described in detail in order to avoid unnecessarily obscuring the present application. Therefore, the specific embodiments disclosed below are not intended to limit the scope of the present application, but merely to illustrate exemplary embodiments of the present application.

[0076] In the description of the application, it should be understood that the orientation or positional relationship indicated by the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the application.

[0077] In addition, the terms "first", "second" are only for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the technical features indicated. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise explicitly specified and limited.

[0078] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connection", "fixing" and the like should be understood broadly, for example, it can be fixed connection, or detachable connection, or integral; it can be mechanical connection, or electrical connection; it can be directly connected, or indirectly connected through intermediate medium, it can be the internal communication of two elements or the interaction relationship between two elements, unless otherwise explicitly limited. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0079] In the present application, unless otherwise explicitly specified and limited, the first feature is "on" or "under" the second feature, which can be direct contact between the first and second features, or indirect contact between the first and second features through intermediate medium. Moreover, the first feature "above", "above" and "above" the second feature can be directly above or obliquely above the first feature, or only indicate that the horizontal height of the first feature is higher than that of the second feature. The first feature "below", "below" and "below" the second feature can be directly below or obliquely below the first feature, or only indicate that the horizontal height of the first feature is less than that of the second feature.

[0080] It is to be noted that when an element such as a layer, film, region or substrate is referred to as being "on" or "connected to" another element, it can be directly on or connected to the other element or intervening elements can also be present. In addition, it is to be noted that the term "connected" can refer to physical or electrical connection. The terms "on", "connected" and "adjacent" as used herein refer to an absolute positioning, unless otherwise indicated. The terms "upper" and "lower" as used herein refer to relative positioning, unless otherwise indicated.

[0081] Referring to Figures 1-4 , Figure 10 and Figures 12-14 , Figure 1 a schematic diagram of an electric machine is shown; Figure 2 Referring to Figure 1 an exploded view of the parts of the electric machine shown in Fig. 1 is shown; Figure 3 Referring to Figure 2 a first schematic diagram of the bracket 400 of the electric machine shown in Fig. 1 is shown; Figure 4 Referring to Figure 2 a second schematic diagram of the bracket 400 of the electric machine shown in Fig. 1 is shown; Figure 10 Referring to Figure 1 a second schematic diagram of the internal structure of the electric machine shown in Fig. 1 is shown; Figure 12 Referring to Figure 10 a partial enlarged view of D of the electric machine shown in Fig. 1 is shown; Figure 13 Referring to Figure 1 a third schematic diagram of the internal structure of the electric machine shown in Fig. 1 is shown; Figure 14 Referring to Figure 13 a partial enlarged view of E of the electric machine shown in Fig. 1 is shown.

[0082] The electric machine provided by the embodiment of the present application comprises a gear box 100 and a prime mover arranged axially with the gear box 100. The prime mover comprises a motor cover 200, a motor assembly 300 and a bracket 400. The motor assembly 300 is arranged in the motor cover 200, and the motor assembly 300 comprises a stator core 310 fixed in the motor cover 200. The bracket 400 is arranged axially between the motor assembly 300 and the gear box 100, and a first axial positioning structure is arranged between the bracket 400 and the stator core 310, and a second axial positioning structure is arranged between the bracket 400 and the housing of the gear box 100. It is to be noted that the axial direction of the electric machine is the yy' direction shown in Fig. 1. Figure 8

[0083] ​The researchers find that the traditional motor in the process of running, its own vibration is larger, and prone to larger spark, so that the motor is prone to damage, shorter service life. Ultimately after many research and analysis found that, because the motor cover 200 and gear box 100 own structure is larger, and mostly by injection molding or casting, thus the position precision of the bearing hole and connecting hole of the bearing installed on the top. When the motor cover 200 and gear box 100 through the set on the output shaft of the upper bearing 610 and lower bearing 620 to realize positioning, then through the locking piece to realize the connection, the distance between the axis of the motor cover 200 and gear box 100 is larger, so that the output shaft in the rotation of its own rotation axis, the rotation axis of one end relative to the axis of the motor cover 200 rotation, and the other end of the rotation axis relative to the axis of the gear box 100 rotation, so that the rotation axis of both ends of the output shaft is low, so that the motor in the process of running, the output shaft is prone to relative to the motor cover 200 and gear box 100 shaking, thus making the vibration of the whole motor is larger, the collision spark is larger, so as to be prone to damage, and the output shaft is prone to deformation and damage, the service life of the whole motor is shorter.

[0084] The motor provided by the application, when it is assembled, the motor assembly 300 is arranged in the motor cover 200, and the stator core 310 of the motor assembly 300 is fixedly connected with the motor cover 200; then the bracket 400 is connected with the stator core 310 fixedly connected with the motor cover 200 along the axial direction through the first axial positioning structure; the bracket 400 is connected with the shell of the gear box 100 through the second axial positioning structure, so that the motor cover 200 and the gear box 100 are assembled. Because the installation precision of the bracket 400 and the stator core 310 can be ensured through the first axial positioning structure in the assembling process, and the stator core 310 is fixedly connected with the motor cover 200, the coaxiality of the bracket 400 and the motor cover 200 is high. The installation precision of the bracket 400 and the gear box 100 can be ensured through the second axial positioning structure, so that the coaxiality of the bracket 400 and the gear box 100 is high. The coaxiality of the motor cover 200 and the gear box 100 is high. The vibration of the output shaft connected with the motor cover 200 and the gear box 100 is small when rotating in the process of running of the motor, and it is not prone to generate larger spark, so that the whole motor is not prone to damage, and the service life is long.

[0085] In one embodiment, the motor cover 200 is provided with a first mounting cavity 210, and the motor assembly 300 is at least partially arranged in the first mounting cavity 210.

[0086] The structure of the motor is described in detail below. Please refer to Figures 5-9 and Figure 11 . Figure 5A schematic diagram of the motor is shown Figure 2 A schematic diagram of the fan 500 of the motor is shown; Figure 6 A schematic diagram of the motor is shown Figure 5 A top view of the fan 500 of the motor is shown; Figure 7 A schematic diagram of the motor is shown Figure 6 A sectional view of the fan 500 of the motor along A-A is shown; Figure 8 A schematic diagram of the motor is shown Figure 1 A schematic diagram of the internal structure of the motor is shown; Figure 9 A schematic diagram of the motor is shown Figure 8 A partial enlarged view of B of the motor is shown; Figure 11 A schematic diagram of the motor is shown Figure 10 A partial enlarged view of C of the motor is shown.

[0087] Referring to Figure 2 , Figure 10 and Figure 12 , the first axial positioning structure of the motor provided by an embodiment of the present application comprises a first positioning column 410 and a first positioning hole 311 which are one-to-one corresponding and mutually matched to position the bracket 400 and the stator core 310 in the axial direction. Through the one-to-one corresponding and mutually matched first positioning column 410 and first positioning hole 311, the installation precision of the bracket 400 and the stator core 310 in the axial direction is ensured, thereby making the coaxiality of the bracket 400 and the stator core 310 higher, and the assembly between the column and the hole is also more convenient.

[0088] Referring to Figure 10 and Figure 12 , the first positioning hole 311 of the motor provided by an embodiment of the present application is arranged on the side of the stator core 310 along the axial direction towards the bracket 400; and the first positioning column 410 is arranged on the side of the bracket 400 along the axial direction towards the stator core 310. Since the stator core 310 is formed by stamping and various fasteners, the stamping is of a thin-walled structure, and thus the first positioning hole 311 is easily machined on the stator core 310, so the first positioning hole 311 is arranged on the side of the stator core 310 along the axial direction towards the bracket 400, and the first positioning column 410 is arranged on the side of the bracket 400 along the axial direction towards the stator core 310. In one specific embodiment, the bracket 400 is formed by injection molding, and thus the first positioning column 410 is easily machined on the bracket 400.

[0089] In one embodiment, the first positioning post 410 is in clearance fit with the first positioning hole 311, and the clearance d1 between the first positioning post 410 and the first positioning hole 311 satisfies the condition: 0.05mm≤d1≤0.15mm. By the clearance fit between the first positioning post 410 and the first positioning hole 311, and by making the clearance d1 therebetween range between 0.05mm and 0.15mm, the bracket 400 can be easily inserted into the first positioning hole 311 while the bracket 400 and the stator core 310 are assembled, and the bracket 400 and the stator core 310 are not easily shaken, so that the coaxiality between the bracket 400 and the stator core 310 can be kept at a high level.

[0090] In one specific embodiment, the clearance between the first positioning post 410 and the first positioning hole 311 is 0.05mm, so that the first positioning post 410 and the first positioning hole 311 are not easily shaken after being fitted. In another specific embodiment, the clearance between the first positioning post 410 and the first positioning hole 311 is 0.10mm, and in still another specific embodiment, the clearance between the first positioning post 410 and the first positioning hole 311 is 0.15mm, so that the first positioning post 410 can be easily inserted into the first positioning hole 311.

[0091] Referring to Figure 3 and Figure 4 In one embodiment, the first positioning post 410 is in clearance fit with the first positioning hole 311, and the clearance d1 between the first positioning post 410 and the first positioning hole 311 satisfies the condition: 0.05mm≤d1≤0.15mm. By the clearance fit between the first positioning post 410 and the first positioning hole 311, and by making the clearance d1 therebetween range between 0.05mm and 0.15mm, the bracket 400 can be easily inserted into the first positioning hole 311 while the bracket 400 and the stator core 310 are assembled, and the bracket 400 and the stator core 310 are not easily shaken, so that the coaxiality between the bracket 400 and the stator core 310 can be kept at a high level.

[0092] In one specific embodiment, the first axial positioning structure includes two groups of first positioning posts 410, so that the first axial positioning structure includes four first positioning posts 410, which work together to ensure the installation precision of the bracket 400 and the stator core 310. It should be noted that the number of groups of first positioning posts 410 is not limited, and can be increased or decreased according to the size of the entire motor. For example, when the motor is large in size, the first axial positioning structure can include three or four groups of first positioning posts 410; when the motor is small in size, the first axial positioning structure can include only one group of first positioning posts 410.

[0093] Referring to Figure 3 、 Figure 4 and Figure 9 , the bracket 400 of the motor provided by the embodiment of the present application is further provided with a positioning protrusion 430 on the side close to the stator core 310 in the axial direction. When the first positioning post 410 cooperates with the first positioning hole 311, the positioning protrusion 430 abuts against the stator core 310. Since the bracket 400 is injection molded, when cooled and formed, the bracket 400 as an injection molded part will inevitably shrink. Since the stator core 310 is made of metal, the shrinkage degree after forming is not the same as that of the bracket 400 made of plastic, so it is difficult to ensure that the contact surfaces of the bracket 400 and the stator core 310 are all fitted, which leads to the instability of the stator core 310 placed on the bracket 400. By providing the positioning protrusion 430, when the first positioning post 410 cooperates with the first positioning hole 311, the positioning protrusion 430 can abut against the stator core 310, so that the bracket 400 and the stator core 310 are not easy to tilt relative to each other, and the position precision between them is high. At the same time, since the positioning protrusion 430 is provided, the area of the contact surface between the bracket 400 and the stator core 310 is small, and only the flatness of the end surface of the positioning protrusion 430 close to the stator core 310 needs to be ensured during processing, so the requirement for the overall processing precision of the bracket 400 is reduced, and it is not necessary to make the processing precision of the entire end surface of the bracket 400 close to the stator core 310 meet a high level, so the processing time and cost of the entire bracket 400 are low.

[0094] In one embodiment, the height h of the positioning protrusion 430 in the axial direction satisfies the condition: 0.1mm≤h≤0.3mm. By setting the height h of the positioning protrusion 430 to be between 0.1mm and 0.3mm, the distance between the bracket 400 and the stator core 310 is small, and thus when the motor assembly 300 is cooled, the air flow is less likely to flow out from between the bracket 400 and the stator core 310. In one specific embodiment, the height h of the positioning protrusion 430 is 0.1mm, so that the distance between the bracket 400 and the stator core 310 is small, and the air flow is less likely to flow out from between the bracket 400 and the stator core 310. In another specific embodiment, the height h of the positioning protrusion 430 is 0.2mm, and in yet another specific embodiment, the height h of the positioning protrusion 430 is 0.3mm, and the positioning protrusion 430 is easy to process.

[0095] Referring to Figure 13 and Figure 14 , the second axial positioning structure of the motor provided by one embodiment of the present application includes a second positioning column 420 and a second positioning hole 110 that correspond to each other and cooperate with each other to position the bracket 400 and the housing of the gearbox 100 in the axial direction. By the second positioning column 420 and the second positioning hole 110 that correspond to each other and cooperate with each other, the installation accuracy of the bracket 400 and the gearbox 100 in the axial direction is ensured, and thus the coaxiality of the bracket 400 and the gearbox 100 is high, and the assembly between the column and the hole is also convenient.

[0096] Referring to Figure 14 , in one embodiment, the second positioning column 420 is arranged on the side of the bracket 400 that faces the housing of the gearbox 100 in the axial direction, and the second positioning hole 110 is arranged on the side of the gearbox 100 that faces the bracket 400 in the axial direction. In another embodiment, the second positioning column 420 is arranged on the side of the gearbox 100 that faces the bracket 400 in the axial direction, and the second positioning hole 110 is arranged on the side of the bracket 400 that faces the housing of the gearbox 100 in the axial direction. It should be noted that since the bracket 400 and the gearbox 100 are both cast, it is not limited whether the second positioning column 420 is arranged on the bracket 400 or the gearbox 100, and it can be adjusted adaptively according to the structural characteristics of the bracket 400 and the gearbox 100.

[0097] In one of the embodiments, the second positioning post 420 is in clearance fit with the second positioning hole 110, and the clearance d2 between the second positioning post 420 and the second positioning hole 110 satisfies the condition: 0.05mm≤d2≤0.15mm. Through the clearance fit between the second positioning post 420 and the second positioning hole 110, and the clearance d2 between them is in the range of 0.05mm-0.15mm. In this way, when the support 400 is assembled with the gear box 100, the second positioning post 420 is easily inserted into the first positioning hole 311 while the two are not easily shaken, so that the coaxiality between the support 400 and the gear box 100 can always be in a higher state. In one of the specific embodiments, the clearance between the second positioning post 420 and the second positioning hole 110 is 0.05mm, so that the second positioning post 420 and the second positioning hole 110 are not easily shaken after being fitted. In another specific embodiment, the clearance between the second positioning post 420 and the second positioning hole 110 is 0.10mm, and in still another specific embodiment, the clearance between the second positioning post 420 and the second positioning hole 110 is 0.15mm, so that the second positioning post 420 is easily inserted into the second positioning hole 110.

[0098] Referring to Figure 10 and Figure 11 , an embodiment of the present application provides the stator core 310 and the motor cover 200 of the motor are provided with a third axial positioning structure. Through the third axial positioning structure, the coaxiality between the stator core 310 and the motor cover 200 is higher. Through the cooperation of the first axial positioning structure and the third axial positioning structure, the coaxiality between the support 400 and the motor cover 200 is higher.

[0099] Referring to Figure 11 , an embodiment of the present application provides the third axial positioning structure of the motor includes a third positioning post 220 and a third positioning hole 312 which are one-to-one corresponding and cooperated to position the motor cover 200 and the stator core 310 in the axial direction. Through the one-to-one corresponding and cooperating third positioning post 220 and third positioning hole 312, the installation precision of the motor cover 200 and the stator core 310 in the axial direction is ensured, so that the coaxiality between the motor cover 200 and the stator core 310 is higher, and the assembly between the post and the hole is also more convenient.

[0100] Referring to Figure 11In an embodiment of the present application, the third positioning column 220 of the motor is arranged on the side of the motor cover 200 axially close to the stator core 310, and the third positioning hole 312 is arranged on the side of the stator core 310 axially away from the bracket 400. Since the stator core 310 is formed by stamping and various fasteners, the stamping is of a thin-walled structure, and the third positioning hole 312 is easily machined on the stator core 310, so the third positioning hole 312 is arranged on the side of the stator core 310 axially away from the bracket 400, and the third positioning column 220 is arranged on the side of the motor cover 200 axially close to the stator core 310. In one specific embodiment, the motor cover 200 is formed by casting, so the third positioning column 220 is easily machined on the motor cover 200.

[0101] In one embodiment, the third positioning column 220 and the third positioning hole 312 are in clearance fit, and the clearance d3 between the third positioning column 220 and the third positioning hole 312 satisfies the condition: 0.05mm≤d3≤0.15mm. Through the clearance fit of the third positioning column 220 and the third positioning hole 312, and the clearance d3 between them is in the range of 0.05mm-0.15mm. In this way, when the motor cover 200 is assembled with the stator core 310, the third positioning column 220 is easily inserted into the third positioning hole 312 while the two are not easily shaken, so that the coaxiality between the motor cover 200 and the stator core 310 can always be in a high state. In one specific embodiment, the clearance between the third positioning column 220 and the third positioning hole 312 is 0.05mm, so that the third positioning column 220 and the third positioning hole 312 are not easily shaken after being fitted. In another specific embodiment, the clearance between the third positioning column 220 and the third positioning hole 312 is 0.10mm, and in still another specific embodiment, the clearance between the third positioning column 220 and the third positioning hole 312 is 0.15mm, so that the third positioning column 220 is easily inserted into the third positioning hole 312.

[0102] In one specific embodiment, the third positioning hole 312 and the first positioning hole 311 are through, to form a through hole, facilitating machining on the stator core 310. Of course, in other embodiments, the third positioning hole 312 and the first positioning hole 311 can also not be through, both being blind holes, which are not specially limited.

[0103] Please refer to Figure 2 and Figure 8The motor assembly 300 of the motor provided by an embodiment of the present application further comprises a rotating connecting component 330 and a rotor core 320 installed on the rotating connecting component 330; the stator core 310 is configured to be arranged around the rotor core 320 with a gap between the stator core 310 and the rotor core 320, and the motor assembly 300 is connected with the gear box 100 through the rotating connecting component 330 for inputting power to the gear box 100. The electromagnetic force generated between the stator core 310 and the rotor core 320 further causes the rotating connecting component 330 installed on the rotor core 320 to rotate, thereby inputting power to the gear box 100 to realize the transmission of power of the motor. In one specific embodiment, the rotating connecting component 330 is an output shaft, and the rotor core 320 is sleeved on the output shaft and is in interference fit with the output shaft.

[0104] Referring to Figure 2 and Figure 8 The motor prime mover provided by an embodiment of the present application further comprises an upper bearing 610 and a lower bearing 620; the upper bearing 610 is sleeved on one end of the rotating connecting component 330 and is connected with the motor cover 200; the lower bearing 620 is sleeved on the other end of the rotating connecting component 330 and is connected with the gear box 100; and the rotor core 320 is located between the upper bearing 610 and the lower bearing 620. Specifically, the inner rings of the upper bearing 610 and the lower bearing 620 are in interference fit with the rotating connecting component 330, the outer ring of the upper bearing 610 is in interference fit with the motor cover 200, the outer ring of the lower bearing 620 is in interference fit with the gear box 100, and the rotor core 320 is arranged between the upper bearing 610 and the lower bearing 620 because it is accommodated in the first installation cavity 210.

[0105] Referring to Figure 2 and Figure 8 The motor prime mover provided by an embodiment of the present application further comprises a fan 500, which is arranged between the bracket 400 and the lower bearing 620, is sleeved on the rotating connecting component 330 and is fixedly connected with the rotating connecting component 330, and can at least partially extend into the bracket 400; the motor cover 200, the bracket 400 and the fan 500 can collectively surround to form an airflow passage. Because the fan 500 can at least partially extend into the bracket 400 and an airflow passage is collectively surrounded by the motor cover 200, the bracket 400 and the fan 500, when the rotating connecting component 330 rotates around its own rotation axis, the airflow formed by the flowing air driven by the fan 500 can flow through the airflow passage, so that the airflow can be concentrated, thereby realizing the ventilation and heat dissipation effect of the motor assembly 300. Specifically, the airflow path in the airflow passage is indicated by arrows in Figure 8 .

[0106] Referring to Figure 1 and Figure 8The motor cover 200 of the motor provided by the embodiment of the present application is also provided with an air inlet 230 and an air outlet 240; when the fan 500 rotates around the rotation axis of the rotation connecting component 330, the airflow can flow into the airflow ventilation channel through the air inlet 230 and flow out through the air outlet 240. When the fan 500 rotates around the rotation axis of the rotation connecting component 330, the air in the first mounting cavity 210 can be driven to flow, and the air pressure in the first mounting cavity 210 is reduced. At this time, the air in the external environment is sucked into the first mounting cavity 210 from the air inlet 230, so that the air in the first mounting cavity 210 flows, and the air can exchange heat with the motor assembly 300 which generates heat during use, so as to reduce the temperature of the motor assembly 300. Finally, the flowing air flows out to the external environment from the air outlet 240 through the airflow ventilation channel.

[0107] Please refer to Figure 1 and Figure 8 The air inlet 230 and the air outlet 240 of the motor provided by the embodiment of the present application are oppositely arranged at the two ends of the motor cover 200 along the axial direction. Since the air inlet 230 and the air outlet 240 are arranged at the two ends of the motor cover 200 along the axial direction, the air in the external environment can flow into the motor cover 200 from one end of the motor cover 200 along the axial direction and flow out from the other end of the motor cover 200 along the axial direction. The flow path of the airflow generated by the air in the first mounting cavity 210 is long, so that the air in the entire first mounting cavity 210 can flow and exchange, and the heat dissipation effect of the motor assembly 300 is better.

[0108] Please refer to Figure 8 and combine Figures 5-7 The bracket 400 of the motor provided by the embodiment of the present application is constructed with a mounting hole 440; the fan 500 includes a mounting base 510 and a plurality of blades 520 which are arranged on the mounting base 510 and spaced from each other along the circumferential direction; each blade 520 includes a first stepped blade 521 and a second stepped blade 522 which are distributed in a stepped manner from the inside to the outside along the radial direction of the mounting base 510; the first stepped blade 521 can extend into the mounting hole 440, and the second stepped blade 522 is oppositely arranged with the end face of the bracket 400 which is away from the stator core 310. By arranging the blades 520 in a stepped structure, the first stepped blade 521 can extend into the mounting hole 440, and the second stepped blade 522 is oppositely arranged with the end face of the bracket 400, so that the entire airflow ventilation channel can be in a relatively closed state, the amount of airflow leakage from the mounting hole 440 is small, the flow of the airflow in the first mounting cavity 210 is large, and the heat dissipation effect of the motor assembly 300 is better.

[0109] Please continue to refer to Figure 8When the motor is in operation, the fan 500 rotates synchronously under the rotation of the rotating connecting part 330, so that the air pressure in the first installation cavity 210 is reduced, and the air in the external environment is drawn into the first installation cavity 210 through the air inlet 230 on the upper side of the yy' direction and flows through the air flow passage in the direction of the arrow, passes through the first installation cavity 210, flows from the first stepped blade 521 to the second stepped blade 522, and finally flows out through the air outlet 240 on the lower side of the yy' direction, so as to realize the flow and exchange of the air in the whole first installation cavity 210 and achieve the heat dissipation of the motor assembly 300. Figure 8 Figure 8 The air in the external environment is drawn into the first installation cavity 210 through the air inlet 230 on the upper side of the yy' direction and flows through the air flow passage in the direction of the arrow, passes through the first installation cavity 210, flows from the first stepped blade 521 to the second stepped blade 522, and finally flows out through the air outlet 240 on the lower side of the yy' direction, so as to realize the flow and exchange of the air in the whole first installation cavity 210 and achieve the heat dissipation of the motor assembly 300.

[0110] Please refer to Figures 5-7 The first stepped blade 521 and the second stepped blade 522 of the motor provided by the embodiment of the present application are configured as an integrated structure. Since the first stepped blade 521 and the second stepped blade 522 are configured as an integrated structure, the fan 500 is easy to process, and the whole blade 520 has a better guiding effect on the air flow, and the air flow is not blocked when flowing along the inclined direction of the blade 520.

[0111] Please refer to Figure 7 The installation base 510 of the motor provided by the embodiment of the present application is inclined along the radial direction thereof from the inside to the outside and from the top to the bottom. That is, the installation base 510 is arranged to be inclined along the radial direction thereof from the inside to the outside and toward one side of the gear box 100. Since the installation base 510 is arranged to be inclined, and the inclined direction thereof is along the radial direction thereof from the inside to the outside and toward one side of the gear box 100, the inclined direction of the installation base 510 is adapted to the stepped direction of the blade 520, so that the height of the whole blade 520 along the axial direction is relatively balanced, which avoids the appearance of a large-thickness block in the installation base 510, so as to prevent the large-thickness block from being deformed in a large area due to shrinkage after injection molding cooling. Therefore, the fan 500 of this structure is not only easy to process the blade 520, but also has a better guiding effect on the air flow.

[0112] In one of the embodiments, the bracket 400 is accommodated in the motor cover 200 and is in clearance fit with the motor cover 200, and the minimum clearance d4 between the bracket 400 and the motor cover 200 satisfies the condition: 0.1mm≤d4≤0.3mm. By setting the minimum clearance d4 between the bracket 400 and the motor cover 200 to be between 0.1mm and 0.3mm, the distance between the bracket 400 and the motor cover 200 is small, which effectively improves the sealing performance of the air flow passage and reduces the air flow from the bracket 400 and the motor cover 200.

[0113] ​In one specific embodiment, the bracket 400 is made of high-strength material, so that the bracket 400 is not easy to deform during use of the motor, thereby effectively ensuring the stability of the coaxial accuracy of the motor cover 200 and the gear box 100.

[0114] Referring to Figure 2 The motor assembly 300 provided by the embodiment of the present application further comprises a stator winding 340, which is arranged between the stator core 310 and the rotor core 320 and connected with the stator core 310. Since the present motor has the stepped distribution of the blades 520, the gap between the bracket 400 and the stator core 310 is small, and the gap between the outer wall of the bracket 400 and the motor cover 200 is also small, so that the air flow passage has good airtightness. In this way, the air flow in the air flow passage is improved, and the heat dissipation effect of the motor assembly 300 is good.

[0115] Since the heat dissipation effect of the motor assembly 300 provided by the present application is good, the stator winding 340 of the motor is made of aluminum wire. Through tests, the stator winding 340 made of aluminum wire can completely meet the heat dissipation requirements of the motor assembly 300, and compared with the stator winding 340 made of copper wire, the entire motor is lighter in weight, lower in cost, and better in economic benefit.

[0116] Referring to Figure 2 and Figure 10 The prime mover of the motor provided by the embodiment of the present application further comprises a first connecting piece 710 and a second connecting piece 720. After the bracket 400, the stator core 310 and the motor cover 200 are positioned and connected through the first axial positioning structure and the third axial positioning structure, the first connecting piece 710 sequentially passes through the three, so that the three are fixedly connected, so that they are not easy to shake after installation. After the bracket 400 and the gear box 100 are positioned and connected through the second axial positioning structure, the second connecting piece 720 is used to fixedly connect the two, so that the two are not easy to shake. In one specific embodiment, the first connecting piece 710 is a self-tapping screw, and the second connecting piece 720 is a screw.

[0117] The present application further provides an electric tool comprising the motor of any one of the above embodiments, which can achieve at least one of the above technical effects.

[0118] The electric tool provided by the present application further comprises a cutting blade connected with the motor. When the cutting blade is driven to move by the electric tool, the vibration of the entire motor tool is small, the noise is small, the electric tool is not easy to be damaged, and the service life is long.

[0119] Any combination of the technical features in the above-described embodiments can be made, and for the sake of brevity, not all possible combinations are described, however, as long as the combination of the technical features does not exist in contradiction, it shall be considered within the scope of the present disclosure.

[0120] The above-described embodiments only express several implementation manners of the present application, and the description is relatively specific and detailed, but it shall not be understood as a limitation on the patent scope of the present application. It shall be pointed out that, for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the present application, and these shall be within the protection scope of the present application. Therefore, the protection scope of the present application patent shall be subject to the appended claims.

Claims

1. An electric machine, comprising: a gear box (100); a prime mover arranged axially with the gear box (100); characterized in that the prime mover comprises: a machine cover (200); and a machine assembly (300) arranged in the machine cover (200), the machine assembly (300) comprising a stator core (310) fixed in the machine cover (200); a rotating connecting component (330) and a rotor core (320) mounted on the rotating connecting component (330); the stator core (310) is configured to be arranged around the rotor core (320) with a gap therebetween, the machine assembly (300) is connected with the gear box (100) through the rotating connecting component (330) for inputting power to the gear box (100); and a bracket (400) arranged axially between the machine assembly (300) and the gear box (100), a first axial positioning structure is arranged between the bracket (400) and the stator core (310); a second axial positioning structure is arranged between the bracket (400) and a housing of the gear box (100); a third axial positioning structure is arranged between the stator core (310) and the machine cover (200); when the electric machine is assembled, the machine assembly (300) is arranged in the machine cover (200) first, the stator core (310) of the machine assembly (300) is fixedly connected with the machine cover (200), and the coaxiality of the stator core (310) and the machine cover (200) is improved through the third axial positioning structure; then the bracket (400) is connected axially with the stator core (310) fixedly connected in the machine cover (200) through the first axial positioning structure; the bracket (400) is connected with the housing of the gear box (100) through the second axial positioning structure, so as to realize the assembly of the machine cover (200) and the gear box (100); the prime mover further comprises a lower bearing (620) and a fan (500), the lower bearing (620) is sleeved on the other end of the rotating connecting component (330) and connected with the gear box (100); the outer ring of the lower bearing (620) is interference-fitted with the gear box (100), and the fan (500) is arranged between the bracket (400) and the lower bearing (620); the machine cover (200), the bracket (400) and the fan (500) can collectively form an air flow channel; the machine cover (200) is further provided with an air inlet (230) and an air outlet (240) arranged axially opposite to the two ends of the machine cover (200), the air inlet (230) is arranged away from the fan (500), and the air outlet (240) is arranged close to the fan (500), so that the fan (500) is located downstream of the air flow channel. When the fan (500) rotates around the rotation axis of the rotation connecting component (330), air flow can flow into the air flow ventilation channel through the air inlet (230) and flow out through the air outlet (240); After the bracket (400), the stator core (310) and the motor cover (200) are positioned and connected through the first axial positioning structure and the third axial positioning structure, a first connecting piece (710) sequentially penetrates through the bracket (400), the stator core (310) and the motor cover (200) to realize fixed connection of the three.

2. The electric machine of claim 1, wherein, The first axial positioning structure comprises a first positioning column (410) and a first positioning hole (311) which correspond to each other and cooperate with each other to position the bracket (400) and the stator core (310) in the axial direction.

3. The electric machine of claim 2, wherein, The first positioning hole (311) is arranged on the side of the stator core (310) facing the bracket (400) in the axial direction. The first positioning column (410) is arranged on the side of the bracket (400) facing the stator core (310) in the axial direction.

4. The electric machine of claim 2, wherein, The first positioning column (410) and the first positioning hole (311) are in clearance fit. The clearance d1 between the first positioning column (410) and the first positioning hole (311) satisfies the condition: 0.05mm≤d1≤0.15mm.

5. The electric machine of claim 2, wherein, The first axial positioning structure comprises at least one group of first positioning columns. Each group of first positioning columns comprises two first positioning columns (410) which are opposite in the radial direction.

6. The electric machine of claim 2, wherein, The side of the bracket (400) close to the stator core (310) in the axial direction is further provided with a positioning protrusion (430). When the first positioning column (410) cooperates with the first positioning hole (311), the positioning protrusion (430) abuts against the stator core (310).

7. The electric machine of claim 6, wherein, The height h of the positioning protrusion (430) in the axial direction satisfies the condition: 0.1mm≤h≤0.3mm.

8. The electric machine of claim 1, wherein, The second axial positioning structure comprises a second positioning column (420) and a second positioning hole (110) which correspond to each other and cooperate with each other to position the bracket (400) and the housing of the gearbox (100) in the axial direction.

9. The electric machine of claim 8, wherein, The second positioning column (420) is arranged on the side of the bracket (400) facing the housing of the gearbox (100) in the axial direction; the second positioning hole (110) is arranged on the side of the gearbox (100) facing the bracket (400) in the axial direction; or The second positioning column (420) is arranged on the side of the gearbox (100) facing the bracket (400) in the axial direction; the second positioning hole (110) is arranged on the side of the bracket (400) facing the housing of the gearbox (100) in the axial direction.

10. The electric machine of claim 9, wherein, The second positioning column (420) and the second positioning hole (110) are in clearance fit. The clearance d2 between the second positioning column (420) and the second positioning hole (110) satisfies the condition: 0.05mm≤d2≤0.15mm.

11. The electric machine of claim 1, wherein, The third axial positioning structure comprises a third positioning column (220) and a third positioning hole (312) which are in one-to-one correspondence and cooperate with each other to position the motor cover (200) and the stator core (310) in the axial direction.

12. The electric machine of claim 11, wherein, The third positioning column (220) is arranged on the side of the motor cover (200) close to the stator core (310) in the axial direction; and the third positioning hole (312) is arranged on the side of the stator core (310) away from the bracket (400) in the axial direction.

13. The electric machine of claim 11, wherein, The third positioning column (220) and the third positioning hole (312) are in clearance fit; The clearance d3 between the third positioning column (220) and the third positioning hole (312) satisfies the condition: 0.05mm≤d3≤0.15mm.

14. The electric machine of claim 1, wherein, The prime mover further comprises an upper bearing (610); The upper bearing (610) is sleeved on one end of the rotating connecting component (330) and connected with the motor cover (200); The rotor core (320) is located between the upper bearing (610) and the lower bearing (620).

15. The electric machine of claim 1, wherein, The fan (500) can at least partially extend into the bracket (400).

16. The electric machine of claim 1, wherein, The bracket (400) is configured with a mounting hole (440); The fan (500) comprises a mounting base (510) and a plurality of blades (520) arranged on the mounting base (510) at intervals in the circumferential direction; each blade (520) comprises a first stepped blade (521) and a second stepped blade (522) which are distributed in a stepped manner from the inside to the outside in the radial direction of the mounting base (510); The first stepped blade (521) can extend into the mounting hole (440), and the second stepped blade (522) is arranged opposite to the end face of the side of the bracket (400) away from the stator core (310).

17. The electric machine of claim 16, wherein, The first stepped blade (521) and the second stepped blade (522) are configured as an integral structure.

18. The electric machine of claim 17, wherein, The mounting base (510) is arranged to be inclined from the inside to the outside in the radial direction thereof toward the side of the gear box (100).

19. The electric machine of any of claims 1-18, wherein, The bracket (400) is accommodated in the motor cover (200) and is in clearance fit with the motor cover (200); The minimum clearance d4 between the bracket (400) and the motor cover (200) satisfies the condition: 0.1mm≤d4≤0.3mm.

20. A power tool, characterized by The motor comprises the motor as claimed in any one of claims 1-19.

21. The power tool of claim 20, wherein, The electric tool further comprises a cutting blade; The cutting blade is connected with the motor.

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