Outer rotor direct-driven electric tool

Abstract

The invention provides an outer rotor direct-drive electric tool which comprises a handle, a head shell, an outer rotor motor and a working head, the outer rotor motor comprises an outer rotor and a stator, the outer rotor comprises a rotor magnet yoke assembly, fan blades and an output shaft, the stator comprises a stator iron core and a plurality of coils, and the stator iron core sleeves the output shaft and is rotationally connected with the output shaft; the output end of the output shaft penetrates through the bearing seat to the outer side of the head shell and is fixedly connected with the working head; the rotor magnet yoke assembly sleeves the stator and is fixedly connected with the output shaft through the fan blades; the rotor magnet yoke assembly comprises a rotor magnet yoke and a plurality of magnetic sheets, a plurality of closed clamping grooves are distributed in the inner wall of the rotor magnet yoke at intervals in the circumferential direction, and the clamping grooves are formed in the axial direction of the rotor magnet yoke; the magnetic sheets are matched with the clamping grooves in shape, are embedded into the clamping grooves to realize radial fixation, and are also bonded with the clamping grooves through glue; a plurality of protrusions matched with the clamping grooves in shape are arranged on the sides, facing the rotor magnet yoke, of the fan blades at intervals, and the protrusions are embedded into the clamping grooves so that the protrusions can be in interference fit with the clamping grooves.

Description

Technical Field

[0001] This invention relates to the field of power tool technology, and more particularly to an external rotor direct drive power tool. Background Technology

[0002] Power tools use a motor to drive the working head to work on the workpiece. In the angle grinder industry of power tools, the working head includes grinding discs, cutting discs, grinding wheels, polishing discs, wire wheels and other discs with a certain degree of sharpness.

[0003] Currently, electric motors generally do not directly drive the working head. Instead, a reduction gear mechanism is used to reduce the motor speed, thereby increasing the torque to achieve the rated speed and torque required for operation. However, the gears in the reduction gear mechanism wear out too quickly, leading to a shortened lifespan for power tools. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides an external rotor direct-drive power tool, including a handle, a head housing, an external rotor motor, and a working head. The head housing is disposed at the head end of the handle, and the external rotor motor is disposed inside the head housing. The external rotor motor includes an external rotor and a stator. The external rotor includes a rotor yoke assembly, a fan blade, and an output shaft. The stator includes a stator core and several coils. Several teeth are spaced apart on the outer circumference of the stator core, and the coils are wound on the teeth. The stator core is sleeved on the output shaft, and the stator core and the output shaft are rotatably connected by at least one first bearing. The lower end of the head housing has an opening, and a bearing seat is fixedly disposed at the opening. The stator core is fixedly connected to the bearing seat. The output end of the output shaft passes through the bearing seat to the outside of the head housing and is fixedly connected to the working head. The output shaft is connected to the working head via a first bearing. Two bearings are rotatably connected to the bearing housing; the non-output end of the output shaft is rotatably connected to the head shell through a third bearing; the rotor yoke assembly is sleeved on the stator, and the upper end of the rotor yoke assembly is fixedly connected to the output shaft through the fan blade; the rotor yoke assembly includes a rotor yoke and several magnetic plates, the rotor yoke is a cylindrical structure with openings at both the top and bottom, the inner wall of the rotor yoke has several tapered slots spaced circumferentially, the slots are arranged along the axial direction of the rotor yoke; the magnetic plates are adapted to the shape of the slots, the magnetic plates are embedded in the slots to achieve radial fixation, and the magnetic plates are also bonded to the slots with glue to achieve axial fixation; the side of the fan blade facing the rotor yoke has several protrusions spaced apart that are adapted to the shape of the slots, the protrusions are embedded in the slots so that the protrusions and the slots are interference fit.

[0005] Optionally, the inner wall of the rotor yoke is provided with a plurality of reinforcing ribs spaced apart circumferentially, and the reinforcing ribs are arranged along the axial direction of the rotor yoke, with the groove formed between two adjacent reinforcing ribs.

[0006] Optionally, the outer periphery of the fan blade is provided with an outer ring on the side facing the rotor yoke, and the outer ring is inserted into the rotor yoke; a plurality of the protrusions are spaced apart on the end face of the outer ring facing the rotor yoke.

[0007] Optionally, at the end furthest from the fan blade, the end face of the reinforcing rib is flush with the end face of the rotor yoke; at the end closer to the fan blade, the end face of the reinforcing rib is located inside the rotor yoke and has a certain distance between it and the end face of the rotor yoke; the outer ring is located within this space and is interference-fitted with the rotor yoke.

[0008] Optionally, the outer ring is also bonded to the rotor yoke with adhesive.

[0009] Optionally, the slot opening faces the central axis of the rotor yoke, and the width of the slot opening is smaller than the width of the slot bottom.

[0010] Optionally, a braking structure is also included, the braking structure including the fan blade and a brake pin, the brake pin being elastically disposed at the top of the head shell and disposed opposite to the fan blade; the fan blade is provided with at least one brake hole on the side facing the brake pin, and the brake pin is inserted into the brake hole by pressing the brake pin.

[0011] Optionally, the fan blade is provided with an insert on the side facing the brake pin, and the brake hole is formed on the insert.

[0012] Optionally, the fan blades are made of aluminum alloy, magnesium alloy or zinc alloy.

[0013] Optionally, the external rotor direct-drive power tool further includes a tool-free mounting cover, which is installed at the lower end of the bearing housing. The cover includes a mounting plate and a mounting edge. The mounting plate is a hollow disc, the hollow part of which allows the lower end of the bearing housing to pass through. At least one latch is provided on the inner circumference of the disc, protruding inward from the inner circumferential surface of the disc. The latch mates with a mounting groove on the outer circumference of the mounting edge at the lower end of the bearing housing. When the latch aligns with the mounting groove, the mounting plate engages with the inner side of the mounting edge, where the inner side of the mounting edge refers to the side of the mounting edge closest to the lower end of the bearing housing. On one side, after the protective cover mounting plate rotates relative to the bearing seat, the mounting edge locks the protective cover mounting plate at the lower end of the bearing seat; the disc is provided with at least one positioning hole, which is used to restrict the relative rotation between the protective cover mounting plate and the bearing seat when the positioning bead at the lower end of the bearing seat is aligned with the positioning hole. The positioning bead is configured such that when the protective cover mounting plate and the bearing seat are subjected to force and rotate relative to each other, its surface is located below the protective cover mounting plate, and when it is aligned with the positioning hole, its surface protrudes from the positioning hole; the protective cover edge is provided on the outer edge of the protective cover mounting plate; the protective cover edge surrounds a part of the protective cover mounting plate.

[0014] Optionally, the handle is a hollow shell structure, and the head shell and the handle are connected by a vent, which is located near the lower end of the head shell; an air outlet is opened at the upper end of the head shell, and an air inlet is opened at the tail end of the handle; there is a gap between the rotor yoke assembly and the stator; the air inlet, the vent, the gap, the fan blade, and the air outlet are sequentially connected to form an air duct.

[0015] Optionally, the handle is equipped with a controller, which is electrically connected to the external rotor motor and is located inside the air duct.

[0016] Optionally, the handle's tail end is further provided with a lithium battery pack, the lithium battery pack including a battery pack housing and a plurality of battery cells, the battery pack housing including a battery box, a battery bracket and a buffer portion, the bottom of the battery box having a plurality of through holes; the battery bracket being disposed within the battery box, the battery bracket including a plurality of battery mounting positions, the plurality of battery cells being respectively mounted in the plurality of battery mounting positions; the buffer portion at least covers the bottom outer side of the battery box and extends through the through holes to between the bottom of the battery box and the bottom of the battery bracket.

[0017] Optionally, the working head is clamped to the output end of the output shaft by a pressure plate assembly; the pressure plate assembly includes a first pressure plate and a second pressure plate, the first pressure plate being sleeved on the output end of the output shaft; the output end of the output shaft is provided with a limiting step for limiting the first pressure plate, the limiting step being located above the first pressure plate; the second pressure plate is threadedly connected to the output end of the output shaft, and the working head is clamped between the first pressure plate and the second pressure plate; The external rotor direct-drive power tool also includes an integrated auxiliary handle, which comprises a wrench, an auxiliary handle portion, and a connecting portion. The wrench is used to disassemble the second pressure plate. The auxiliary handle portion is provided with a receiving cavity for accommodating the wrench. The opening of the receiving cavity is located at the rear end of the auxiliary handle portion, and a fixing unit is provided at the bottom of the receiving cavity for detachably fixing the wrench. The wrench is fixed to the fixing unit when not in use. The connecting portion is connected to the front end of the auxiliary handle portion. The connecting portion is used to detachably fix the auxiliary handle portion to the head shell, or to detachably fix the wrench to the auxiliary handle portion. The wrench is fixed to the connecting portion when in use.

[0018] Compared with the prior art, the technical solution of the embodiments of the present invention has the following beneficial effects: The power tool provided by this invention uses an external rotor motor to directly drive the working head. It can reduce speed and increase torque to achieve the rated speed and torque required during operation without the need for a reduction gear mechanism. Since there is no need for a reduction gear mechanism, there is no problem of rapid gear wear, thereby improving the service life of the power tool.

[0019] Furthermore, in the rotor yoke assembly, the magnetic sheet is embedded in the slot of the rotor yoke. The magnetic sheet is axially fixed by radial fixation through the slot and glue bonding. Therefore, the magnetic sheet will not fall off even under large torque.

[0020] Furthermore, the present invention embeds the protrusion of the fan blade into the slot of the inner wall of the rotor yoke, and fixes the fan blade and the rotor yoke by interference fit. Therefore, even under a large torque, the rotor yoke will not detach from the fan blade.

[0021] Furthermore, since the fan blade plays a rigid transmission role between the rotor yoke assembly and the output shaft, the fan blade has a certain strength. This invention uses the fan blade as the main body of the braking structure, which simplifies the structure of the power tool and can reduce the height of the power tool, allowing the power tool to be used in narrow spaces. Furthermore, the fan blades are made of high-strength aluminum alloy (magnesium alloy or zinc alloy), which increases the strength of the fan blades and prevents them from being damaged or detached from the output shaft during braking.

[0022] Furthermore, the integrated auxiliary handle provided by the present invention includes a wrench, an auxiliary handle portion, and a connecting portion. The connecting portion is connected to the front end of the auxiliary handle portion, allowing the auxiliary handle portion to be detachably connected to the head shell for assisting in gripping the power tool. The auxiliary handle portion is provided with a receiving cavity, and a fixing unit is provided at the bottom of the receiving cavity. When not in use, the wrench can be connected to the fixing unit and hidden inside the auxiliary handle portion, making it less likely to be lost. When needed, i.e., when the second pressure plate needs to be removed, the wrench can be detached from the fixing unit, and the auxiliary handle portion can also be detached from the head shell. Then, the wrench is fixedly connected to the connecting portion. The wrench is operated by gripping the auxiliary handle portion, providing a good feel, allowing for force application, and facilitating operation.

[0023] Furthermore, the tool-free installation and removal cover provided by this invention aligns the mounting slot with the buckle, and then rotates it to lock the tool-free installation and removal cover in place, thus completing the installation. During disassembly, simply rotate the mounting slot until it aligns with the buckle to remove the tool-free installation and removal cover. No tools are required, and installation and disassembly can be done by hand. In addition, the positioning bead aligns with the positioning hole to achieve locking, and angle positioning can be easily achieved without the need for a trigger switch. Adjustment is convenient and it will not loosen.

[0024] Furthermore, since iron powder generated when the working head is cutting or grinding iron parts is easily attracted to the magnetic plate of the motor by the magnetic field, causing the motor to jam, the present invention sets the air inlet at the tail end of the handle and the air outlet at the upper end of the head shell away from the working head, that is, away from the working area, which greatly prevents iron powder from entering and prevents iron powder from being attracted to the magnetic plate by the magnetic field, causing the motor to jam.

[0025] Furthermore, the lithium battery pack provided by the present invention has a buffer section that not only covers the bottom of the battery pack housing, but also extends through a through hole to the space between the bottom of the battery pack housing and the bottom of the battery bracket, thus supporting the battery bracket. When there is vibration, it can not only dampen the battery box, but also buffer the space between the battery bracket and the battery box. Through the integrated buffer section, a dual damping effect is achieved, resulting in better damping performance.

[0026] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1This is a schematic diagram of the structure of an external rotor direct drive power tool according to an embodiment of the present invention; Figure 2 This is an exploded view of the structure of an external rotor motor according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the rotor yoke provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the structure of a wind turbine blade provided in an embodiment of the present invention; Figure 5 A perspective view of a wind turbine blade provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of an integrated auxiliary handle in one state according to an embodiment of the present invention; Figure 7 This is a schematic diagram of the assembly of the integrated auxiliary handle and the head shell according to an embodiment of the present invention; Figure 8 This is a cross-sectional view of another state of the integrated auxiliary handle according to an embodiment of the present invention; Figure 9 This is an exploded view of an integrated auxiliary handle in one state according to an embodiment of the present invention; Figure 10 An exploded view of an integrated auxiliary handle in one state according to another embodiment of the present invention; Figure 11 This is a schematic diagram of a non-removable protective cover according to an embodiment of the present invention; Figure 12 This is a schematic diagram of a non-removable protective cover and bearing housing as viewed from the bottom direction according to an embodiment of the present invention; Figure 13 This is a schematic diagram of the installation of a non-removable protective cover according to an embodiment of the present invention; Figure 14 This is an exploded view of a non-removable protective cover according to an embodiment of the present invention; Figure 15 This is a schematic diagram of the air inlet structure according to an embodiment of the present invention; Figure 16 This is a schematic diagram of the air outlet structure according to an embodiment of the present invention; Figure 17 This is a top view of the lithium battery pack of the present invention without the battery holder; Figure 18 This is a cross-sectional view along the AA direction of the lithium battery pack of the present invention without the battery holder. Figure 19 This is a cross-sectional view of the lithium battery pack after the battery holder has been placed according to the present invention. Detailed Implementation

[0029] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0030] The terms "first," "second," "third," "fourth," etc. (if present) in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus. The terms "above" and "over," and any variations thereof, are intended to describe positional relationships and do not imply direct contact between the described objects.

[0031] Please refer to Figures 1 to 5 An embodiment of the present invention provides an external rotor direct drive power tool, including a handle 12, a head housing 7, an external rotor motor 6 and a working head 1. The head housing 7 is disposed at the head end of the handle 12, and the external rotor motor 6 is disposed inside the head housing 7.

[0032] The external rotor motor 6 includes an external rotor and a stator 603. The stator 603 includes a stator core 6031 and several coils 6032. The stator core 6031 has several teeth spaced apart on its outer circumference, and the coils 6032 are wound around these teeth. The stator core 6031 is sleeved on the output shaft 604, and the stator core 6031 and the output shaft 604 are rotatably connected by at least one first bearing 11. The lower end of the head housing 7 has an opening, and a bearing seat 4 is fixedly mounted at the opening. The stator core 6031 is fixedly connected to the bearing seat 4. The output end 6041 of the output shaft 604 passes through the bearing seat 4 to the outside of the head housing 7 and is fixedly connected to the working head 1. The output shaft 604 is rotatably connected to the bearing seat 4 via a second bearing 3; the non-output end of the output shaft 604 is rotatably connected to the head housing 7 via a third bearing 8.

[0033] This embodiment does not limit the specific type of the working head 1, such as a cutting disc, grinding wheel, wire wheel, polishing wheel, etc.

[0034] Since the coil 6032 is energized when the external rotor motor 6 is running, and the bearing housing 4 is made of conductive metal, in order to prevent the coil 6032 from conducting electricity through contact with the bearing housing 4, an insulating sleeve 5 is provided on the outer periphery of the bearing housing 4 near the coil 6032, and the parts of the stator core 6031 that come into contact with the coil 6032 before winding are coated to achieve an insulation effect.

[0035] The outer rotor includes a rotor yoke assembly 602, a fan blade 601, and an output shaft 604. The rotor yoke assembly 602 is fitted onto the stator 603, and its upper end is fixedly connected to the output shaft 604 via the fan blade 601. The rotor yoke assembly 602 includes a rotor yoke 6022 and several magnetic plates 6021. The rotor yoke 6022 is a cylindrical structure open at both ends. Several tapered slots 60222 are distributed circumferentially along the inner wall of the rotor yoke 6022. The slots 60222 are arranged axially along the rotor yoke 6022. The magnetic plates 6021 are adapted to the shape of the slots 60222. The magnetic plates 6021 are embedded in the slots 60222 for radial fixation, and are also bonded to the slots 60222 with adhesive for axial fixation. The fan blade 601 has several protrusions 6012 at intervals on the side facing the rotor yoke 6022, which are adapted to the shape of the slot 60222. The protrusions 6012 are embedded in the slot 60222, so that the protrusions 6012 and the slot 60222 are interference fit.

[0036] In this invention, when the external rotor motor 6 is working, an electromagnetic field is generated by the stator 603. The magnetic sheet 6021 is driven by the electromagnetic force of the electromagnetic field to rotate the rotor yoke 6022. The torque is transmitted to the output shaft 604 through the fan blade 601. The rotor yoke 6022 causes the output shaft 604 to rotate, thereby realizing the rotation of the working head 1 to perform operations such as cutting, grinding, rust removal, and polishing on metal.

[0037] In this invention, the magnetic sheet 6021 is embedded in the slot 60222 on the inner wall of the rotor yoke 6022. The magnetic sheet 6021 is axially fixed by radial fixation of the slot 60222 and adhesive bonding. Therefore, the magnetic sheet 6021 will not fall off even under a large torque.

[0038] Similarly, in this invention, the protrusion 6012 of the fan blade 601 is embedded in the slot 60222 of the inner wall of the rotor yoke 6022. The fan blade 601 and the rotor yoke 6022 are fixed by interference fit. Therefore, even under a large torque, the rotor yoke 6022 will not detach from the fan blade 601.

[0039] In this embodiment, the opening 602221 of the slot 60222 faces the central axis of the rotor yoke 6022. The slot 60222 is a tapered slot, meaning the width of the opening 602221 is smaller than the width of the bottom 602222. The bottom 602222 of the slot 60222 is opposite to the opening 602221, located on the inner wall of the rotor yoke 60222. The shape of the sidewall of the slot 60222 is not limited in this embodiment; it can be an arc-shaped surface or a flat surface. The shape and size of the protrusions 6012 of the magnetic sheet 6021 and the fan blade 601 are adapted to the slot 60222.

[0040] This embodiment does not limit the number of card slots 60222, and can be set according to actual usage requirements.

[0041] In one specific implementation, the inner wall of the rotor yoke 6022 is provided with a plurality of reinforcing ribs 60221 spaced circumferentially, and the reinforcing ribs 60221 are arranged along the axial direction of the rotor yoke 60222, with a groove 60222 formed between two adjacent reinforcing ribs 60221. This embodiment, by adding reinforcing ribs 60221 to the inner wall of the rotor yoke 6022, can, on the one hand, fix the magnetic sheet 6021, and on the other hand, achieve a more reliable fit with the fan blade 601, thereby increasing the torsional resistance.

[0042] In this specific embodiment, the length direction of the reinforcing rib 60221 is the length direction of the rotor yoke 6022, that is, the length direction of the reinforcing rib 60221 is parallel to the axial direction of the rotor yoke 60222, the width direction of the reinforcing rib 60221 is the circumferential direction of the rotor yoke 60222, and the thickness direction of the reinforcing rib 60221 is the radial direction of the rotor yoke 60222.

[0043] In this embodiment, an outer ring 6011 is provided on the outer periphery of the fan blade 601 facing the rotor yoke 6022, and the outer ring 6011 is inserted into the rotor yoke 6022; a plurality of protrusions 6012 are spaced apart on the end face of the outer ring 6011 facing the rotor yoke 6022.

[0044] At the end furthest from the fan blade 601, the end face of the reinforcing rib 60221 is flush with the end face of the rotor yoke 6022. At the end closer to the fan blade 601, the end face of the reinforcing rib 60221 is located within the rotor yoke 6022, and there is a certain distance between it and the end face of the rotor yoke 6022; the outer ring 6011 is located within this space and is interference-fitted with the rotor yoke 6022.

[0045] In one specific implementation, the card slot 60222 is a dovetail groove structure, and the magnetic sheet 6021 and the protrusion 6012 are both dovetail tenon structures adapted to the shape of the card slot 60222.

[0046] In this embodiment, the magnetic sheet 6021 is first inserted into the card slot 60222, thereby radially fixing the magnetic sheet 6021 to the card slot 60222. To increase the reliability of the fixed connection between the magnetic sheet 6021 and the card slot 60222, adhesive is also used to bond the magnetic sheet 6021 to the card slot 60222, thereby preventing axial movement of the magnetic sheet 6021.

[0047] The outer ring 6011 is inserted into the rotor yoke 6022, resulting in an interference fit between the outer ring 6011 and the rotor yoke 6022. The protrusion 6012 on the outer ring 6011 is inserted into the slot 60222, also resulting in an interference fit between the protrusion 6012 and the slot 60222. To further increase the reliability of the fixed connection between the fan blade 601 and the rotor yoke 6022, adhesive is applied to bond the outer ring 6011 to the rotor yoke 6022.

[0048] In this embodiment, the center of the fan blade 601 is also provided with a shaft hole for fixing the sleeve on the output shaft 604.

[0049] This embodiment does not limit the shape of the shaft hole; it can be a circular hole or a non-circular hole. If the shaft hole is circular, torque is transmitted between the fan blade 601 and the output shaft 604 through friction, which can easily lead to torque transmission failure or efficiency reduction. To avoid this risk, in one specific embodiment, the shaft hole includes a first hole segment and a second hole segment. The first hole segment is a circular hole segment, which is interference-fitted to the output shaft 604. To increase the friction between the circular hole segment and the output shaft 604, knurling 6042 can be provided on the outer surface of the shaft segment of the output shaft 604 that mates with the circular hole segment.

[0050] In one specific implementation, the second bore section is a non-circular bore section 6013, and the output shaft 604 is also provided with a non-circular shaft section 6043 adapted to the non-circular bore section 6013, with the non-circular bore section 6013 and the non-circular shaft section 6043 engaging; or / and, the second bore section and the output shaft 604 are provided with corresponding keyways, and connecting keys are respectively embedded in these two keyways. Therefore, the second bore section and the output shaft 604 transmit torque through a rigid mechanical engagement instead of friction, thereby achieving higher torque reliability, positioning accuracy, and load-bearing capacity.

[0051] This embodiment does not limit the shape of the non-circular hole segment 6013 and the non-circular shaft segment 6043, such as D-shaped, flat square, polygonal, etc.

[0052] This embodiment does not limit the processing technology of the rotor yoke 6022 with the slot 60222. For example, the rotor yoke 6022 can be formed by internal hole broaching, extrusion forming, stretch forming, or stamping and riveting.

[0053] The power tool in this embodiment uses an external rotor motor 6 to directly drive the working head 1. It can reduce speed and increase torque to reach the rated speed and torque required during operation without the need for a reduction gear mechanism. Since there is no need for a reduction gear mechanism, there is no problem of rapid gear wear, which improves the service life of the power tool.

[0054] Existing power tools typically have motors with an output speed of 7000 r / min. To achieve the same torque of 1 N·m, a motor with a speed of 18000 r / min and a transmission ratio of approximately 2.6 would only bear a torque of 0.38 N·m. However, this embodiment uses a direct-drive external rotor motor 6, allowing the motor to directly bear the 1 N·m torque. In this embodiment, the magnetic sheet 6021 is embedded in the slot of the rotor yoke 6022. The magnetic sheet 6021 is radially fixed within the slot and then bonded axially with adhesive. Therefore, even under significant torque, the magnetic sheet 6021 will not detach.

[0055] This invention does not limit the number of teeth on the outer periphery of the stator core or the number of magnetic plates 6021; these can be set according to actual usage requirements. Since the stator is generally three-phase, the number of teeth must be a positive integer multiple of 3, preferably not less than 6. More teeth result in more coils 6032, leading to a more uniform distribution of electromagnetic force. Correspondingly, the number of magnetic plates 6021 must be a positive integer multiple of 2. In this embodiment, the number of magnetic plates 6021 is 10, increasing the number of pole pairs compared to a typical inner rotor, thereby achieving low-speed, high-torque output shaft operation.

[0056] In this embodiment, the working head 1 is clamped to the output end 6041 of the output shaft by the pressure plate assembly 2; the pressure plate assembly 2 includes a first pressure plate 201 and a second pressure plate 202, the first pressure plate 201 is sleeved on the output end 6041 of the output shaft 604; the output end 6041 of the output shaft 604 is provided with a limiting step for limiting the first pressure plate 201, the limiting step is located above the first pressure plate 201; the second pressure plate 202 is threadedly connected to the output end 6041 of the output shaft 604, and the working head 1 is clamped between the first pressure plate 201 and the second pressure plate 202.

[0057] When disassembling and assembling the working head 1, the second pressure plate 202 needs to be removed from the output end 6041 of the output shaft 604 before the working head 1 can be removed from the output end 6041 of the output shaft 604. Since the second pressure plate 202 is threadedly connected to the output end 6041 of the output shaft 604, the output shaft 604 of the external rotor motor 6 will rotate when the second pressure plate 202 is removed, making disassembly and assembly very inconvenient. Operators often need to use other external parts to fix the output shaft 604, which is time-consuming and laborious. To solve this technical problem, the power tool provided in this embodiment also includes a braking structure, which includes the fan blade 601 and a brake pin 10. The brake pin 10 is elastically disposed at the top of the head housing 7 and is positioned opposite to the fan blade 601. The fan blade 601 has at least one brake hole 6014 on the side facing the brake pin 10. By pressing the brake pin 10, the brake pin 10 is inserted into the brake hole 6014, thereby braking the output shaft 604 and enabling the disassembly and assembly of the working head 1.

[0058] In one specific implementation, the fan blade 601 is closer to the non-output end of the output shaft 604 than the stator 603 and the rotor yoke 6022, in order to facilitate the installation of the brake pin 10 on the head housing 7.

[0059] In order to facilitate the automatic reset of the brake pin 10 when it is released, the brake pin 10 is elastically set on the head shell 7 by the return spring 9.

[0060] Specifically, the brake pin 10 includes an integrally formed pin body 1002 and a pressing part 1001. The top of the head shell 7 is provided with a mounting through hole. The pin body 1002 is elastically disposed in the mounting through hole by a return spring 9. The pressing part 1001 is disposed away from the fan blade 601.

[0061] During braking, pressing the pressing part 1001 causes the pin body 1002 to insert into the brake hole 6014, thereby braking the output shaft 604. After the working head 1 is disassembled and assembled, the pressing part 1001 is released, and the pin body 1002 is reset by the action of the return spring 9, thereby disengaging from the brake hole 6014.

[0062] Braking holes 6014 can be provided on the structure of the fan blade 601 or on the insert of the fan blade 601. This embodiment does not impose any specific restrictions on this.

[0063] In one specific embodiment, the fan blade 601 includes a web 6015, an outer ring 6011, and a plurality of blades 6016. The web 6015 has a non-circular hole section 6013 at its center. The fan blade 601 is fitted onto the output shaft 604 by an interference fit, and a non-circular hole section 6013 is provided in a portion to fix the non-circular shaft section 6043 of the output shaft 604.

[0064] The outer ring 6011 is located on the outer periphery of the web 6015. A plurality of protrusions 6012 are circumferentially arranged on the side of the outer ring 6011 facing the rotor yoke 6022. The protrusions 6012 are embedded in the slots 60222 of the rotor yoke 6022.

[0065] A plurality of blades 6016 are spaced apart between the web 6015 and the outer ring 6011, and there are gaps between the plurality of blades 6016 to facilitate heat dissipation of the motor.

[0066] To further increase the reliability of the connection between the fan blade 601 and the output shaft 604, the center of the web plate 6015 is provided with an axial extension section 6017 on the side opposite to the brake pin 10. The axial extension section 6017 is fixedly sleeved on the knurled surface 6042 of the output shaft 604.

[0067] In this embodiment, since the fan blade 601 plays a rigid transmission role between the rotor yoke assembly 602 and the output shaft 604, the fan blade 601 has a certain strength. The present invention uses the fan blade 601 as the main body of the braking structure, which simplifies the structure of the power tool and can reduce the height of the power tool, so that the power tool can be used in narrow spaces.

[0068] The web plate 6015 is provided with a reinforcing rib 6018 on the side opposite to the brake pin 10, and / or the fan blade 601 is made of aluminum alloy, magnesium alloy, or zinc alloy. The purpose is to increase the strength of the fan blade 601 and prevent the fan blade 601 from being damaged or falling off the output shaft 604 during braking.

[0069] Please refer to Figures 6 to 10 In this embodiment, the tool for disassembling the second pressure plate 202 is an integrated auxiliary handle, which includes: an auxiliary handle part 15, a connecting part 16, and a wrench 17. The auxiliary handle part 15 is used to assist in gripping the power tool and is also used to operate the wrench 17 to disassemble the second pressure plate 202 of the power tool.

[0070] Specifically, the connecting part 16 is connected to the front end of the auxiliary handle part 15 (i.e. Figure 6 (At the right end of the middle), when it is necessary to remove the second pressure plate 202, i.e., when the wrench 17 is used, the connecting part 16 is used to detachably fix the wrench 17 to the auxiliary handle part 15, such as Figure 6As shown, the second pressure plate 202 is disassembled by operating the wrench 17 by gripping the auxiliary handle 15. The wrench 17 is detachably fixed within the auxiliary handle 15 when not in use; specifically, please refer to... Figure 8 The auxiliary handle 15 is provided with a receiving cavity 1501 for receiving the wrench 17. The opening of the receiving cavity 1501 is located at the rear end of the auxiliary handle (i.e., Figure 8 At the left end of the cavity 1501, a fixing unit is provided at the bottom for detachably fixing the wrench 17. When not in use, the wrench 17 is snapped into the fixing unit, i.e., hidden inside the auxiliary handle 15, to prevent loss. When the power tool needs to be operated, the connecting part 16 is used to detachably fix the auxiliary handle 15 to the head shell 7, such as... Figure 7 As shown, the power tool is held with the help of the auxiliary handle 15.

[0071] In this embodiment, the fixing unit takes the snap-fit ​​structure 1502 as an example, such as... Figure 8 , Figure 9 As shown, the snap-fit ​​structure 1502 is used to detachably engage the wrench 17.

[0072] In another embodiment, the fixing unit can also be a magnetic suction element 1504, such as... Figure 10 As shown, the magnetic component 1504 is used to detachably attract the wrench 17. The corresponding part of the wrench 17 can be directly set as a metal part that can be attracted magnetically, or a metal part that can be attracted magnetically can be set at a corresponding position on the wrench 17.

[0073] In one embodiment, the fixing unit and the bottom of the receiving cavity 1501 can be connected by screws. Preferably, the screws can be self-tapping screws 1503, such as... Figure 9 , Figure 10 As shown, the snap-fit ​​structure 1502 or the magnetic component 1504 is fixed to the bottom of the receiving cavity 1501 by the self-tapping screw 1503.

[0074] In one embodiment, a protruding portion 1505 protruding outward from the surface is provided at the front end near the auxiliary handle, such as... Figure 6 , Figure 8 , Figure 9 , Figure 10 As shown. The protrusion 1505 provides better protection for the hand, preventing it from slipping inward and coming into contact with the machine or the working head 1.

[0075] In one embodiment, the connection between the connecting part 16 and the head shell 7 can be achieved by a threaded connection. Specifically, the outer wall of the connecting part 16 is provided with an external thread 1601, such as... Figure 9 , Figure 10 As shown; the head shell 7 is provided with a threaded hole that matches the thread of the connecting part 16.

[0076] In one embodiment, the wrench includes a wrench head 1701, a connecting plate 1702, and a wrench body 1703 arranged sequentially, such as... Figure 9 As shown. The wrench head 1701 is used to connect with the connecting part 16; in this embodiment, the snap-fit ​​structure 1502 detachably snaps the wrench 17, which is also achieved by snapping the wrench head 1701. In addition, the wrench head 1701 and the connecting plate 1702 are distributed at a right angle, and the wrench body 1703 and the connecting plate 1702 are distributed at an obtuse angle, and the wrench head 1701 and the wrench body 1703 are located on the same side of the connecting plate 1702. The lower end face of the wrench body 1703 is provided with at least one force-applying protrusion 1704. In this embodiment, two are used as an example. The lower end face of the wrench body 1703 refers to the end face of the wrench body 1703 away from the wrench head 1701. When disassembling the working head 1, the force-applying protrusion 1704 can be inserted into the limiting hole of the second pressure plate 202 to apply rotational force. With the design of the wrench structure in this embodiment, the wrench 17 occupies little space when stored in the receiving cavity 1501, making it easy to store. In addition, after the wrench head 1701 is connected to the connecting part 16, the auxiliary handle part 15 and the wrench body 1703 are also distributed at an obtuse angle. At this angle, when the hand holds the auxiliary handle part 15 to operate, it can reasonably avoid the power tool guard, and the operation is convenient and labor-saving.

[0077] In practice, the connection between the wrench head 1701 and the connecting part 16 can be achieved by means of threads. The wrench head 1701 is provided with a hole 17011, and the hole 17011 is provided with internal threads. When connection is required, the front end of the connecting part 16 is inserted into the hole 17011, and then the external thread of the front end of the connecting part 16 is screwed into the internal thread of the wrench hole 17011 to complete the fixing of the wrench 17.

[0078] In a preferred embodiment, a nut 17012 can also be welded onto the wrench head 1701. This nut 17012 matches the external thread at the front end of the connecting part 16, thus making the connection between the wrench head 1701 and the connecting part 16 more stable. Figure 6 As shown.

[0079] In different embodiments, the number of force-applying protrusions 1704 is not necessarily two. For example, when there are three limiting holes on the second pressure plate 202, the number of force-applying protrusions 1704 can also be three, etc. The number of force-applying protrusions is not limited here.

[0080] In one embodiment, the snap-fit ​​structure 1602 includes: a connector 15021 and two spring clips 15022, such as... Figure 9As shown. Connector 15021 is connected to the bottom of receiving cavity 1501. Two spring pieces 15022 are respectively disposed at both ends of connector 15021, and are respectively tilted away from the bottom of receiving cavity 1501; the middle part of one spring piece 15022 forms a recess 150221 towards the other spring piece 15022. When wrench 17 is idle, wrench head 1701 faces the bottom of receiving cavity 1501. When wrench 1701 is pressed down, the two spring pieces 15022 are squeezed outward and deformed. Wrench head 1701 passes downward through recess 150221, and the opposite sides of wrench head 1701 are respectively engaged with the lower parts of the two spring pieces 15022. The lower parts of spring pieces 15022 refer to the part of spring piece 15022 located between connector 15021 and recess 150221. When the wrench 17 is needed, pull the wrench 17 outward, the two spring pieces 15022 are squeezed and deformed outward, the wrench head 1701 passes outward through the recess 150221, and the wrench 1701 is taken out from the snap-fit ​​structure 1502.

[0081] In one embodiment, the wrench body 1703 is also provided with an avoidance hole 17031, such as... Figure 9 As shown, the output end 6041 of the output shaft 604 of the external rotor motor 6 is used to avoid the output of the external rotor motor 6. The figure shows an example with two force-applying protrusions 1704, which correspond to two limiting holes on the second pressure plate 202. The two limiting holes are located at both ends of the threaded hole of the pressure plate, and the avoidance hole 17031 is also located between the two force-applying protrusions 1704. Compared to the previous method where the wrench body 1703 was made narrower to avoid the output end 6041 of the output shaft 604, and thus positioned to the side of the output end 6041 of the output shaft 604, in this embodiment, by providing the clearance hole 17031, the wrench body 1703 can be made wider, resulting in a more stable structure. In addition, when using the wrench to remove the second pressure plate 202, the output shaft 604 passes through the clearance hole 17031. When applying force, in addition to the restriction between the force-applying protrusion 1704 on the wrench 17 and the limiting hole on the second pressure plate 202, the restriction of the output shaft 604 on the wrench is also added, making the operation of the wrench more stable.

[0082] In one embodiment, the outer surface of the auxiliary handle portion 15 is covered with an adhesive layer 1506, such as... Figure 8 As shown, it has a better feel and greater friction, making it easier to operate.

[0083] The working principle of the integrated auxiliary handle: When it is necessary to operate the power tool, the integrated auxiliary handle can be fixed on the head shell 7 to assist in gripping the power tool. When it is necessary to disassemble the working head 1, the integrated auxiliary handle is removed from the head shell 7, the wrench 17 is removed from the fixing unit, and then the wrench 17 is fixed on the connecting part 16. The wrench 17 is operated by holding the auxiliary handle part 15 to disassemble the second pressure plate 202.

[0084] Please refer to Figures 11 to 14 In this embodiment, the power tool also includes a tool-free removable cover 18, which includes a cover mounting plate 1801 and a cover edge 1802. The cover mounting plate 1801 is used to mount the tool-free removable cover 18 on the lower end of the bearing seat 4, and the cover edge 1802 is used to surround a part of the working head 1 to isolate and protect that part of the area and prevent splashing.

[0085] Specifically, such as Figure 11 As shown, the protective cover mounting plate 1801 is a hollow disc 18011 in the middle, through which the lower end of the bearing housing 4 passes. Several latches 18012 are provided on the inner circumference of the disc, protruding from the inner circumferential surface of the disc. The latches 18012 match the mounting grooves 4011 on the outer circumference of the mounting edge 401 of the lower end of the bearing housing 4, as shown. Figure 12 As shown; it is used to insert the protective cover mounting plate 1801 into the inner side of the mounting edge 401 when the buckle 18012 is aligned with the mounting groove 4011. The inner side of the mounting edge 401 refers to the side of the mounting edge 401 near the lower end of the bearing housing 4. Then, after the protective cover mounting plate 1801 and the bearing housing 4 rotate relative to each other, that is, when the mounting groove 4011 and the buckle 18012 are no longer aligned, the mounting edge 401 locks the protective cover mounting plate 18011 into the lower end of the bearing housing 4, as shown. Figure 13 As shown, the disc has at least one positioning hole 18013. When the positioning bead 402 at the lower end of the bearing housing 4 is aligned with the positioning hole 18013, the surface of the positioning bead 402 protrudes from the positioning hole 18013, thereby restricting the relative rotation between the protective cover mounting plate 1801 and the bearing housing 4, and thus achieving positioning. When the protective cover mounting plate 18011 and the bearing housing 4 rotate relative to each other under force, the surface of the positioning bead 402 is subjected to pressure from the protective cover mounting plate 1801. The surface of the positioning bead 402 is located below the protective cover mounting plate 18011. When the positioning bead 402 is aligned with the positioning hole 18013, that is, when the surface of the positioning bead 402 is not under pressure, the positioning bead 402 partially protrudes from the positioning hole 18013 and does not fall off. The protective cover edge 1802 is provided on the outer edge of the protective cover mounting plate 1801; the protective cover edge 1802 surrounds a part of the protective cover mounting plate 1801, and the part of the protective cover mounting plate 1801 not surrounded by the protective cover edge 1802 is used for the working head 1 to contact the workpiece for operation.

[0086] In one embodiment, when the buckle 18012 is aligned with the mounting groove 4011 and snapped into the inner side of the mounting edge 401, the protective edge 1802 avoids its working angle.

[0087] In the above embodiment, the tool-free removable cover 18 is installed by aligning the buckle 18012 with the assembly groove 4011, inserting the cover mounting plate 1801 into the inner side of the mounting edge 401, and then rotating it. The tool-free removable cover 18 can then be secured to the lower end of the bearing seat 4 via the mounting edge 401, thus completing the installation. For disassembly, simply rotate the cover until the buckle 18012 aligns with the assembly groove 4011 to remove the tool-free removable cover 18. No tools are required, and installation and disassembly can be done by hand. In addition, the positioning bead 402 is aligned with the positioning hole 18013 to achieve locking, allowing for easy angle positioning without the need for a trigger switch. Adjustment is convenient and will not loosen.

[0088] In one embodiment, the number of snap fasteners 18012 is at least three, and the at least three snap fasteners 18012 include: one wide snap fastener 180121 and at least two adjacent narrow snap fasteners 180122. The width of each narrow snap fastener 180122 is less than the width of the wide snap fastener 180121, and the total width of the at least two narrow snap fasteners 180122 is greater than the width of the wide snap fastener 180121.

[0089] The combination of wide clip 180121 and narrow clip 180122, with the total width of at least two narrow clips 180122 being greater than the width of the wide opening, makes the installation more secure.

[0090] like Figure 12 As shown, taking four buckles 18012 as an example, including one wide buckle 180121 and three adjacent narrow buckles 180122. In this embodiment, the wide buckle 180121 is distributed on one side of the disc, and the three narrow buckles 180122 are distributed on the other side of the disc.

[0091] In different embodiments, the number of clips 18012 may not be as follows. Figure 12 The four in the picture, and the distribution of the 18012 buckles, are not necessarily as shown. Figure 12 As shown; it can be freely set as needed, and there are no restrictions on it.

[0092] In one embodiment, the number of positioning holes 18013 is greater than the number of positioning beads 402, enabling multi-angle positioning. For example... Figure 12 As shown, the number of positioning beads 402 is three, the number of positioning holes 18013 is twelve, and the multiple positioning holes 18013 are evenly distributed along the circumference of the disk.

[0093] In different embodiments, the number of positioning beads 402, the number of positioning holes 18013, and the distribution of positioning beads 402 and positioning holes 18013 are not necessarily the same. Figure 12 The settings shown can be freely configured as needed, and there are no restrictions on them.

[0094] In one embodiment, the bearing housing 4 protrudes from the lower end of the head shell 7, where the lower end of the bearing housing 4 refers to the end of the bearing housing 4 furthest from the head shell 7.

[0095] In one embodiment, the bearing housing 4 includes: a bearing housing body 403, a spring 404, a positioning bead 402, and a positioning bead pressure plate 405, such as Figure 14 As shown. The bearing housing body 403 protrudes from the lower end of the head shell 7. A spring hole recessed inwards from the surface is provided at the lower end of the bearing housing body 403; a spring 404 is disposed in the spring hole. A positioning bead 402 is disposed above the spring 404; a positioning bead pressure plate 405 is fixed to the lower end of the bearing housing body and is used to press the positioning bead 402 onto the spring 404; the positioning bead pressure plate 405 includes a through hole 4051 corresponding to the positioning bead 402. The diameter of the through hole 4051 is slightly smaller than the diameter of the positioning bead 402, used to allow the positioning bead 402 to partially protrude from the lower end of the positioning bead pressure plate 405 without falling off when the positioning bead 402 is not pressed; when pressed, the positioning bead 402 is subjected to downward pressure, causing the spring 404 to contract, and the positioning bead 402 to move downwards.

[0096] In one embodiment, the positioning bead pressure plate 405 can be fixed to the lower end of the bearing housing body 403 by means of screws 406, such as... Figure 14 As shown.

[0097] In one embodiment, there are multiple positioning beads 402, which are distributed at different parts along the circumference of the bearing seat. The arrangement of multiple positioning beads 402 makes the positioning more stable.

[0098] Preferably, there are three positioning beads 402: a first positioning bead 4021, a second positioning bead 4022, and a third positioning bead 4023. The three positioning beads are arranged in a triangle to ensure that the protective cover is firmly supported and will not tilt, making the positioning more stable.

[0099] In one embodiment, the number of snap fasteners 18012 is at least three, and correspondingly, the number of mounting slots 4011 is at least three, such as... Figure 12 In this example, the number of clips 18012 and assembly slots 4011 is four. The three positioning beads are located at the corresponding positions of three different assembly slots 4011. Figure 12 Two of the positioning beads are located at the positions corresponding to the two narrow mounting slots of the two narrow buckles 180122, and the other positioning bead is located at the position corresponding to the wide mounting slot of the wide buckle 180121. The position corresponding to the mounting slot 4011 is relatively wide due to the inward indentation of the mounting slot 4011, providing ample space for setting the positioning beads and facilitating drilling and installation.

[0100] In one embodiment, the number of positioning holes 18013 is a multiple of the number of positioning beads; multiple positioning holes 18013 are evenly distributed on the disk, for example, the number of positioning holes 18013 is four times the number of positioning beads, that is, the number of positioning beads is twelve, such as... Figure 12 As shown. The angle between adjacent positioning holes 18013 is proportional to the angle between adjacent positioning beads, thus allowing for a wider range of positioning angles. Figure 12 In the middle, the angle between adjacent positioning holes 18013 is 30 degrees, the angle between the first positioning bead 4021 and the second positioning bead 4022 is 60 degrees, and the angles between the first positioning bead 4021 and the third positioning bead 4023, and between the second positioning bead 4022 and the third positioning bead 4023 are 150 degrees respectively.

[0101] In different embodiments, the number of positioning holes 18013 is not necessarily as follows. Figure 12 As shown, for example, when the number of positioning beads is three, the number of positioning holes 18013 can also be six, with the six positioning holes 18013 evenly distributed on the disc. The number of positioning holes 18013 can be freely set as needed and is not limited thereto. The distribution of the positioning beads is also not necessarily as shown. Figure 12 As shown, such as, it can be evenly distributed on the disk.

[0102] Please refer to Figure 15 and Figure 16 In this embodiment, the handle 12 is a hollow shell structure. The head shell 7 and the handle 12 are connected by a vent 702, which is located near the lower end of the head shell 7. An air outlet 701 is opened at the upper end of the head shell 7, and an air inlet 1201 is opened at the tail end of the handle 12. There is a gap between the rotor yoke assembly 602 and the stator 603. The air inlet 1201, the vent 702, the gap, the fan blade 601, and the air outlet 701 are sequentially connected to form an air duct. That is, air enters the air duct from the air inlet 1201 and is blown out from the air outlet 701. The purpose is to cool down the controller 13 and the external rotor motor 6 inside the handle 12. Because the iron powder generated when the working head 1 is cutting or grinding iron parts is easily attracted to the magnetic plate 6021 by the magnetic field, causing the motor to jam, in this embodiment, the air inlet 1201 is set at the tail end of the handle 12 and the air outlet 701 is set at the upper end of the head shell 7 away from the working head 1, that is, away from the working area, which greatly prevents the iron powder from entering and prevents the iron powder from being attracted to the magnetic plate 6021 by the magnetic field, thus preventing the motor from jamming.

[0103] In this embodiment, the controller 13 is located inside the handle 12, the controller 13 is electrically connected to the external rotor motor 6, and the controller 13 is located inside the air duct.

[0104] The power tool provided in this embodiment can be powered by a lithium battery pack or connected to a 220V AC power supply via an AC-to-DC driver. This embodiment does not impose any restrictions on this.

[0105] In one specific implementation, the power tool is powered by a lithium battery pack 14, which is located at the end of the handle 12. The lithium battery pack 14 is connected to the external rotor motor 6 via a controller 13.

[0106] Please refer to Figures 17 to 19 Specifically, the lithium battery pack 14 includes a battery pack housing 1401 and several battery cells 1402. The battery pack housing 1401 includes a battery box 14011, a battery bracket 14012, and a buffer portion 14013. The bottom of the battery box 14011 has a through hole 140111 extending through the bottom. Figure 17 As shown. The battery bracket 14012 is disposed inside the battery housing 14011, including a plurality of battery mounting positions 140121, and a plurality of battery cells 1402 are respectively installed in the plurality of battery mounting positions 140121, as shown. Figure 19 As shown. The buffer portion 14013 at least covers the bottom outer side of the battery housing 14011, and extends through the through hole 140111 to the area between the bottom of the battery housing 14011 and the bottom of the battery bracket 14012, and can contact the bottom of the battery bracket 14012, acting as an internal buffer pad, such as... Figure 18 , Figure 19 As shown.

[0107] In the above embodiments, the bottom of the battery box 14011 includes a through hole 140111. When the buffer part 14013 is manufactured, for example, when the buffer part 14013 is formed by rubber coating, the rubber not only covers the bottom of the battery box 14011, but also extends through the through hole 140111 to the space between the bottom of the battery box 14011 and the bottom of the battery bracket 14012. That is, through one injection of glue, while the battery box 14011 is coated with rubber, a buffer pad is also formed inside the battery box 14011. When there is vibration, the buffer part 14013 can not only play a shock-absorbing role for the battery box 14011, but also play a buffering role between the battery bracket 14012 and the battery box 14011. Through the integrated buffer part 14013, a dual shock-absorbing role is achieved, and the shock-absorbing effect is better.

[0108] In one embodiment, the bottom upper surface of the battery housing 14011 includes an upwardly protruding support rib 140112, and the through hole 140111 also penetrates the support rib 140112, such as... Figure 17 , Figure 18 As shown.

[0109] In one embodiment, the support rib 140112 extends laterally along the cell 1402, such as... Figure 17 The diagram shows an extension along the left-right direction.

[0110] In one embodiment, there are two support ribs 140112, which are distributed in parallel. The two support ribs 140112 correspond to the two ends of the longitudinal direction (vertical direction as shown in the figure) of the battery cell 1402, such as... Figure 17 As shown in the image.

[0111] In different embodiments, the number of support ribs 140112 may be two or more, and the remaining support ribs 140112 may be distributed in parallel between the two support ribs 140112 on both sides.

[0112] In one embodiment, the support rib 140112 includes at least one recess 1401121, which corresponds one-to-one with the battery mounting position 140121 near the bottom of the battery housing 14011. Figure 18 As shown, the battery mounting position 140121 includes two rows. The recess 1401121 corresponds one-to-one with the lower battery mounting position 140121 (i.e. the battery mounting position 140121 near the bottom of the battery box 14011), which can provide better support and support for the battery bracket 14012.

[0113] In one embodiment, the through hole 140111 is located at the recess 1401121, and each recess 1401121 corresponds to at least two through holes 140111. The at least two through holes 140111 are distributed along the extending direction of the support rib 140112; there are through holes 140111 on both sides of the middle portion of the recess 1401121. For example... Figure 18 As shown, taking each recess 1401121 as an example, each recess 1401121 corresponds to two through holes 140111. The two through holes 140111 are respectively set on both sides of the middle part of the recess 1401121.

[0114] In different embodiments, the number of through holes 140111 corresponding to each recess 1401121 can also be two or more. For example, when each recess 1401121 corresponds to three through holes 140111, two of the through holes 140111 can be respectively set on both sides of the middle part of the recess 1401121, and the other through hole 140111 can be set in the middle part of the recess 1401121; when each recess 1401121 corresponds to four through holes 140111, two through holes 140111 can be respectively set on both sides of the middle part of the recess 1401121; and so on. Other quantities will not be described one by one and can be freely set as needed.

[0115] In one embodiment, when there are multiple recesses 1401121, the protrusions 1401122 between adjacent recesses 1401121 are provided with holes 14011221, such as... Figure 17 As shown. The protrusion 1401122 between adjacent recesses 1401121 is relatively thick. During the manufacturing of the battery box 14011, this protrusion 1401122 is not easy to solidify and is prone to shrinkage and deformation after demolding. A hole is set at this position to prevent shrinkage.

[0116] like Figure 17 The hole 14011221 shown is a square hole. In different embodiments, it can also be a round hole, a triangular hole, etc. The shape of the hole 14011221 is not limited here, as long as it can achieve the purpose of reducing material and preventing shrinkage.

[0117] In one embodiment, the buffer portion 14013 further extends to cover the lower sidewall of the battery housing 14011, such as... Figure 19 As shown, the lower side wall of the battery housing 14011 refers to the side wall of the battery housing 14011 near the bottom.

[0118] Figure 19 Taking ten battery cells 1402 as an example, the ten battery cells 1402 are arranged in a two-row, five-column configuration. In different embodiments, the number of battery cells 1402 is not necessarily ten, and the number of rows and columns arranged is not necessarily two. There are no restrictions on the number of battery cells 1402 or their arrangement.

[0119] This invention does not limit the specific type of power tool, such as a grinder, angle grinder, etc.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An external rotor direct-drive power tool, characterized in that, The device includes a handle, a head shell, an external rotor motor, and a working head. The head shell is located at the head end of the handle, and the external rotor motor is located inside the head shell. The external rotor motor includes an external rotor and a stator. The external rotor includes a rotor yoke assembly, a fan blade, and an output shaft. The stator includes a stator core and several coils. Several teeth are spaced apart on the outer circumference of the stator core, and the coils are wound around the teeth. The stator core is sleeved on the output shaft, and the stator core and the output shaft are rotatably connected by at least one first bearing. The lower end of the head shell has an opening, and a bearing seat is fixedly installed at the opening. The stator core is fixedly connected to the bearing seat. The output end of the output shaft passes through the bearing seat to the outside of the head shell and is fixedly connected to the working head. The output shaft is rotatably connected to the bearing seat through a second bearing. The non-output end of the output shaft is rotatably connected to the head shell via a third bearing; the rotor yoke assembly is sleeved on the stator, and the upper end of the rotor yoke assembly is fixedly connected to the output shaft via the fan blade; the rotor yoke assembly includes a rotor yoke and several magnetic plates, the rotor yoke is a cylindrical structure with openings at both the top and bottom, the inner wall of the rotor yoke has several tapered slots spaced circumferentially, the slots are arranged along the axial direction of the rotor yoke; the magnetic plates are adapted to the shape of the slots, the magnetic plates are embedded in the slots to achieve radial fixation, and the magnetic plates are also bonded to the slots with glue to achieve axial fixation; the side of the fan blade facing the rotor yoke has several protrusions spaced apart that are adapted to the shape of the slots, the protrusions are embedded in the slots so that the protrusions and the slots are interference fit.

2. The external rotor direct-drive power tool according to claim 1, characterized in that, The inner wall of the rotor yoke is provided with a plurality of reinforcing ribs spaced apart circumferentially, and the reinforcing ribs are arranged along the axial direction of the rotor yoke, with the groove formed between two adjacent reinforcing ribs.

3. The external rotor direct-drive power tool according to claim 2, characterized in that, The outer periphery of the fan blade is provided with an outer ring on the side facing the rotor yoke, and the outer ring is inserted into the rotor yoke; a plurality of the protrusions are spaced apart on the end face of the outer ring facing the rotor yoke.

4. The external rotor direct-drive power tool according to claim 3, characterized in that, At the end furthest from the fan blade, the end face of the reinforcing rib is flush with the end face of the rotor yoke; at the end closest to the fan blade, the end face of the reinforcing rib is located inside the rotor yoke and has a certain distance between it and the end face of the rotor yoke; the outer ring is located within this space and is interference-fitted with the rotor yoke.

5. The external rotor direct-drive power tool according to claim 3, characterized in that, The outer ring is also bonded to the rotor yoke with adhesive.

6. The external rotor direct-drive power tool according to claim 1, characterized in that, The slot opening faces the central axis of the rotor yoke, and the width of the slot opening is smaller than the width of the slot bottom.

7. The external rotor direct-drive power tool according to claim 1, characterized in that, It also includes a braking structure, which includes the fan blade and a brake pin. The brake pin is elastically disposed at the top of the head shell and is disposed opposite to the fan blade. The fan blade has at least one brake hole on the side facing the brake pin. By pressing the brake pin, the brake pin is inserted into the brake hole.

8. The external rotor direct-drive power tool according to claim 7, characterized in that, The fan blade has an insert on the side facing the brake pin, and the brake hole is formed on the insert.

9. The external rotor direct-drive power tool according to claim 1, characterized in that, The fan blades are made of aluminum alloy, magnesium alloy or zinc alloy.

10. The external rotor direct-drive power tool according to claim 1, characterized in that, It also includes a tool-free mounting cover, which is installed at the lower end of the bearing housing. The cover includes a mounting plate and a mounting edge. The mounting plate is a hollow disc, the hollow part of which allows the lower end of the bearing housing to pass through. At least one latch is provided on the inner circumference of the disc, protruding inward from the inner circumferential surface of the disc. The latch matches a mounting groove on the outer circumference of the mounting edge at the lower end of the bearing housing. When the latch aligns with the mounting groove, the mounting plate engages with the inner side of the mounting edge, where the inner side of the mounting edge refers to the side of the mounting edge closest to the lower end of the bearing housing. After the protective cover mounting plate rotates relative to the bearing housing, the mounting edge secures the protective cover mounting plate to the lower end of the bearing housing. The disc has at least one positioning hole, used to restrict relative rotation between the protective cover mounting plate and the bearing housing when the positioning bead at the lower end of the bearing housing aligns with the positioning hole. The positioning bead is configured such that its surface is below the protective cover mounting plate during relative rotation under force, and protrudes from the positioning hole when aligned with it. The protective cover edge is located on the outer edge of the protective cover mounting plate, and surrounds a portion of the protective cover mounting plate.

11. The external rotor direct-drive power tool according to claim 1, characterized in that, The handle is a hollow shell structure. The head shell and the handle are connected by a vent. The vent is located near the lower end of the head shell. An air outlet is opened at the upper end of the head shell, and an air inlet is opened at the tail end of the handle. There is a gap between the rotor yoke assembly and the stator. The air inlet, the vent, the gap, the fan blade, and the air outlet are connected in sequence to form an air duct.

12. The external rotor direct-drive power tool according to claim 1, characterized in that, The handle contains a controller, which is electrically connected to the external rotor motor and is located inside the air duct.

13. The external rotor direct-drive power tool according to claim 1, characterized in that, The handle is also provided with a lithium battery pack at its tail end. The lithium battery pack includes a battery pack shell and a number of battery cells. The battery pack shell includes a battery housing, a battery bracket, and a buffer portion. The bottom of the battery housing has a number of through holes. The battery bracket is disposed in the battery housing and includes a number of battery mounting positions. A number of battery cells are respectively installed in a number of battery mounting positions. The buffer portion covers at least the bottom outer side of the battery housing and extends through the through holes to the area between the bottom of the battery housing and the bottom of the battery bracket.

14. The external rotor direct-drive power tool according to claim 1, characterized in that, The working head is clamped to the output end of the output shaft by a pressure plate assembly; the pressure plate assembly includes a first pressure plate and a second pressure plate, the first pressure plate being sleeved on the output end of the output shaft; the output end of the output shaft is provided with a limiting step for limiting the first pressure plate, the limiting step being located above the first pressure plate; the second pressure plate is threadedly connected to the output end of the output shaft, and the working head is clamped between the first pressure plate and the second pressure plate; The external rotor direct-drive power tool also includes an integrated auxiliary handle, which comprises a wrench, an auxiliary handle portion, and a connecting portion. The wrench is used to disassemble the second pressure plate. The auxiliary handle portion is provided with a receiving cavity for accommodating the wrench. The opening of the receiving cavity is located at the rear end of the auxiliary handle portion, and a fixing unit is provided at the bottom of the receiving cavity for detachably fixing the wrench. The wrench is fixed to the fixing unit when not in use. The connecting portion is connected to the front end of the auxiliary handle portion. The connecting portion is used to detachably fix the auxiliary handle portion to the head shell, or to detachably fix the wrench to the auxiliary handle portion. The wrench is fixed to the connecting portion when in use.

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