CN217063416U

CN217063416U - Brushless motor and electric tool

Info

Publication number: CN217063416U
Application number: CN202123349423.9U
Authority: CN
Inventors: 李保华
Original assignee: Shenzhen Luwei Technology Co ltd
Current assignee: Shenzhen Luwei Technology Co ltd
Priority date: 2021-12-22
Filing date: 2021-12-22
Publication date: 2022-07-26
Anticipated expiration: 2031-12-22

Abstract

The utility model relates to the technical field of electric machine, and provide a brushless motor and electric tool, brushless motor includes that rotor assembly and cover locate the stator assembly outside the rotor assembly, rotor assembly includes rotor shaft, rotor core, a plurality of magnetic steel sheet, two balancing pieces and insulating injection molding, rotor core cover locates outside the rotor shaft, two balancing piece interval covers locate on the rotor shaft and lie in rotor core's relative both sides, a plurality of magnetic steel sheet be the circumference range set up in rotor core department, insulating injection molding wraps up in a plurality of magnetic steel sheet and with the rotor shaft, rotor core, two the balancing piece is connected in order to form an organic whole structure, or, insulating injection molding wraps up in rotor core and with the rotor shaft, magnetic steel sheet and two the balancing piece is connected in order to form an organic whole structure; the utility model discloses utilize the insulating effect of the insulator of moulding plastics to improve the insulating nature between rotor assembly and the stator assembly, and then guarantee brushless motor normal operating.

Description

Brushless motor and electric tool

Technical Field

The utility model relates to the technical field of motors, particularly, relate to a brushless motor and electric tool.

Background

At present, a brushless motor, such as a brushless dc motor, is composed of a motor body and a driver, and the driver can control the motor body to perform operations such as starting, stopping, braking, speed regulation, protection, and the like. The motor main body mainly comprises a rotor assembly and a stator assembly; wherein, the rotor assembly mainly includes rotor shaft, rotor core, two balancing blocks, magnetic steel sleeve and multiple magnetic steel sheets, the rotor core is sleeved outside the rotor shaft, two balancing blocks are sleeved on the rotor shaft at intervals, multiple magnetic steel sheets are distributed along the circumference of the rotor core, the magnetic steel sleeve is sleeved outside the magnetic steel sheets to fix the multiple magnetic steel sheets, the stator assembly is sleeved outside the magnetic steel sleeve in the rotor assembly, because a certain distance is required to be kept between the stator assembly and the rotor assembly constantly to ensure the insulativity between the stator assembly and the rotor assembly, but the magnetic steel sleeve is a tubular structure synthesized by multiple hard strong metals, the distance between the rotor assembly and the stator assembly can be changed slightly in the high-speed rotation process of the rotor assembly relative to the stator assembly, the insulation between the rotor assembly and the stator assembly is reduced, the brushless motor can not normally operate, and the magnetic steel sleeve can generate eddy current loss outside the multiple magnetic steel sheets, thereby affecting the useful life of the rotor assembly.

SUMMERY OF THE UTILITY MODEL

The utility model provides a problem how to improve the insulating nature between rotor assembly and the stator assembly.

In order to solve the problem, the utility model provides a brushless motor, locate including rotor assembly and cover the outer stator assembly of rotor assembly, rotor assembly includes rotor shaft, rotor core, a plurality of magnetic steel piece, two balancing pieces and insulating injection molding, rotor core cover is located outside the rotor shaft, two the balancing piece spacer sleeve is located on the rotor shaft and be located rotor core's relative both sides, it is a plurality of the magnetic steel piece be the circumference arrange set up in rotor core department, insulating injection molding wrap up in a plurality of the magnetic steel piece and with the rotor shaft rotor core, two the balancing piece is connected in order to form a body structure, or, insulating injection molding wrap up in rotor core and with the rotor shaft magnetism and two the balancing piece is connected in order to form a body structure.

Optionally, rotor core's inner wall and/or rotor shaft's outer wall is equipped with first guide way, be equipped with on the balancing piece and be convenient for the feed inlet that insulating injection molding body pours into, the feed inlet with first guide way intercommunication.

Optionally, the number of the first guide groove and the number of the feed inlets are a plurality, the first guide groove is circumferentially distributed along the rotor core and/or the rotor shaft, and the feed inlets are circumferentially distributed along the inner wall of the balance block.

Optionally, a plurality of isolation teeth are arranged on the circumferential outer wall of the rotor core at intervals, a positioning groove is formed between every two adjacent isolation teeth, and each magnetic steel sheet is arranged in each positioning groove.

Optionally, the thickness of the magnetic steel sheets is greater than that of the isolation teeth, a gap is formed between partial structures of two adjacent magnetic steel sheets protruding out of the isolation teeth, and the insulation injection molding body wraps the magnetic steel sheets and fills the gap.

Optionally, one end of the balance block, which deviates from the rotor core, is provided with a feed hole, one end of the balance block, which faces the rotor core, is provided with an annular flow channel, and the feed hole and each of the gaps are respectively communicated with the annular flow channel.

Optionally, a plurality of mounting grooves are formed between the inner wall and the outer wall of the rotor core and arranged in an annular manner, and each of the magnetic steel sheets is embedded in each of the mounting grooves.

Optionally, the stator assembly includes coil support body, stator core, stator winding and a plurality of insulator, be equipped with in the stator core along its circumference a plurality of channels that distribute, each the insulator distributes and inlays and locates each in the channel, the coil support body set up in stator core's axial tip, offer on the coil support body and be used for the threading mouth that stator winding passed.

Optionally, the inner wall of the threading mouth is provided with a sealing rib, part of the structure of the insulating base extends out of the channel, and part of the structure of the insulating base penetrates through the threading mouth and is abutted against the sealing rib.

Optionally, a notch is formed in the channel, an opening is formed in the position, corresponding to the notch, of the insulating seat, and a protrusion used for increasing the insulating distance between the stator winding and the notch is formed in the opening of the insulating seat.

Compared with the prior art, the utility model has the advantages that the rotor core is sleeved outside the rotor shaft, and the two balancing blocks are sleeved on the rotor shaft at intervals and positioned at the two opposite sides of the rotor core, so as to balance the rotor shaft in the rotor assembly in the high-speed rotation process; the plurality of magnetic steel sheets are arranged at the position of the rotor core in a circumferential mode, and the insulation injection molding bodies are wrapped on the magnetic steel sheets and are connected with the rotor shaft, the rotor core, the plurality of magnetic steel sheets and the two balance blocks into an integral structure, in other words, the insulation injection molding bodies are wrapped outside the plurality of magnetic steel sheets to replace magnetic steel sleeves in the prior art; or, the insulation injection molding body is wrapped on the rotor core and connected with the rotor shaft, the magnetic steel sheet and the two balance blocks to form an integral structure, in other words, the insulation injection molding body is wrapped outside the rotor core to replace a magnetic steel sleeve in the prior art, so that the insulation between the magnetic steel sheet or the rotor core and the stator assembly in the rotor assembly is improved by utilizing the insulation effect of the injection molding insulator, the connection tightness between all parts in the rotor assembly can be improved by utilizing the injection molding insulator, and the normal operation of the brushless motor is further ensured; the insulating injection molding body is adopted to replace a magnetic steel sleeve to wrap a plurality of magnetic steel sheets or rotor cores, so that eddy current loss can be reduced in the rotating process, and the service life of the rotor assembly is correspondingly ensured.

The utility model also provides an electric tool, include as above brushless motor.

Since the electric tool comprises all technical solutions of the brushless motor, the electric tool has at least all technical effects of the brushless motor.

Drawings

FIG. 1 is a schematic view of a prior art rotor assembly;

fig. 2 is a schematic structural diagram of a rotor assembly according to an embodiment of the present invention;

FIG. 3 is a schematic view of an exploded structure of a rotor assembly according to an embodiment of the present invention;

FIG. 4 is a second schematic view of an exploded structure of a rotor assembly according to an embodiment of the present invention;

FIG. 5 is an enlarged schematic view of the structure at A in FIG. 4;

fig. 6 is a third schematic view illustrating an exploded structure of a rotor assembly according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a brushless motor according to an embodiment of the present invention;

fig. 8 is an exploded view of a brushless motor according to an embodiment of the present invention;

fig. 9 is an exploded view of the stator assembly according to the embodiment of the present invention;

FIG. 10 is an enlarged view of the structure at B in FIG. 9;

fig. 11 is a schematic structural view of a coil frame body according to an embodiment of the present invention;

fig. 12 is a fourth schematic view illustrating an exploded structure of a rotor assembly according to an embodiment of the present invention;

fig. 13 is a schematic structural diagram of the magnetic steel sheet installed in the rotor core in the embodiment of the present invention.

Description of the reference numerals:

1-a rotor assembly; 11-a rotor shaft; 12-a rotor core; 121-a first guide groove; 122-mounting grooves; 13-magnetic steel sheet; 131-a gap; 14-a weight; 141-a feed inlet; 142-a feed port; 143-annular flow channel; 15-an insulating injection molding body; 16-a spacer tooth; 17-a magnetic steel sleeve; 2-a stator assembly; 21-coil frame body; 211-threading mouth; 212-sealing ribs; 22-a stator core; 23-a stator winding; 24-an insulating seat; 241-opening; 242-bump.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention more comprehensible, embodiments accompanied with figures are described in detail below.

It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or otherwise described herein.

In the description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; may be a mechanical connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

In the description herein, references to the description of the terms "an example," "one example," and "one implementation," etc., mean that a particular feature, structure, material, or characteristic described in connection with the example or implementation is included in at least one example or implementation of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or implementation. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or implementations.

In the prior art, referring to fig. 1, a brushless motor includes a rotor assembly 1 and a stator assembly 2 sleeved outside the rotor assembly 1, wherein the rotor assembly 1 includes a rotor shaft 11, a rotor core 12, two balance blocks 14, a magnetic steel sleeve 17 and a plurality of magnetic steel sheets 13, the rotor core 12 is sleeved outside the rotor shaft 11, the two balance blocks 14 are sleeved on the rotor shaft 11 at intervals, for example, the two balance blocks 14 are respectively sleeved on two sides of the rotor shaft 11 along the axial direction thereof, the plurality of magnetic steel sheets are distributed along the circumferential direction of the rotor core 12, the magnetic steel sleeve 17 is sleeved outside the magnetic steel sheets 13 to fix the plurality of magnetic steel sheets 13, the stator assembly 2 is sleeved outside the magnetic steel sleeve 17 in the rotor assembly 1, since a certain distance needs to be constantly kept between the stator assembly 2 and the rotor assembly 1 to ensure the insulation between the stator assembly 2 and the rotor assembly 1, but the magnetic steel sleeve 17 is a tubular structure synthesized by a plurality of hard strong metals, in the process of high-speed rotation of the rotor assembly 1 relative to the stator assembly 2, the distance between the rotor assembly 1 and the stator assembly 2 is usually slightly changed to reduce the insulation between the rotor assembly 1 and the stator assembly 2, so that the brushless motor cannot operate normally, and the magnetic steel sleeve 17 is sleeved outside the plurality of magnetic steel sheets 13 to generate eddy current loss, thereby affecting the service life of the rotor assembly 1.

In order to solve the above technical problem, as shown in fig. 2 to 4, 7 and 8, an embodiment of the present invention provides a brushless motor, which includes a rotor assembly 1 and a stator assembly 2 sleeved outside the rotor assembly 1, the rotor assembly 1 includes a rotor shaft 11, a rotor core 12, a plurality of magnetic steel sheets 13, two balance blocks 14 and an insulation injection molded body 15, the rotor core 12 is sleeved outside the rotor shaft 11, two balance blocks 14 are sleeved on the rotor shaft 11 and located at two opposite sides of the rotor core 12, a plurality of the magnetic steel sheets 13 are arranged in a circumferential manner at the rotor core 12, the insulation injection molded body 15 is wrapped in a plurality of the magnetic steel sheets 13 and connected with the rotor shaft 11, the rotor core 12, two balance blocks 14 to form an integral structure, or the insulation injection molded body 15 is wrapped in the rotor core 12 and connected with the rotor shaft 11, The magnetic steel sheet 13 and the two balance weights 14 are connected to form an integral structure.

The rotor shaft 11 is a motor shaft of a brushless motor. The rotor iron core 12 is sleeved on the rotor shaft 11 and can synchronously rotate along with the rotor shaft 11; the inner diameter of the rotor core 12 matches the outer diameter of the rotor shaft 11, so that the rotor core 12 is smoothly sleeved outside the rotor shaft 11. The plurality of magnetic steel sheets 13 are arranged outside or inside the rotor core 12 in a circular circumferential arrangement, the number of the magnetic steel sheets 13 is more than two, for example, three, four or five, etc., as long as the plurality of magnetic steel sheets 13 are arranged in a circumferential arrangement and can cover the outside or inside of the rotor core 12, the technical scheme is applicable, and therefore, the number, size and thickness of the magnetic steel sheets 13 are not specifically limited; when the plurality of magnetic steel sheets 13 are respectively arranged on the outer circumference of the rotor core 12, so that the plurality of magnetic steel sheets 13 are not tightly connected with the rotor core 12, and the insulation injection molding bodies 15 are wrapped outside the plurality of magnetic steel sheets 13 and are connected with the rotor core 12, the rotor shaft 11 and the two balance blocks 14 to form an integrated structure; or, when the plurality of magnetic steel sheets 13 are respectively installed inside the rotor core 12, the insulation injection molding body 15 wraps the rotor core 12 and is connected with the rotor shaft 11, the magnetic steel sheets 13 and the two balance blocks 14 to form an integrated structure, so that the insulation between the magnetic steel sheets 13 and the stator assembly 2 can be enhanced by using the insulation injection molding body 15 arranged outside the magnetic steel sheets 13, the brushless motor can be ensured to normally and continuously operate, and the connection tightness between each component in the rotor assembly 1 can be enhanced.

In this embodiment, the rotor core 12 is sleeved outside the rotor shaft 11, and the two balance blocks 14 are sleeved on the rotor shaft 11 at intervals and located at two opposite sides of the rotor core 12, so as to balance the rotor shaft 11 in the rotor assembly 1 in the high-speed rotation process; the plurality of magnetic steel sheets 13 are arranged at the position of the rotor core 12 in a circumferential manner, and the insulating injection molding body 15 is wrapped on the magnetic steel sheets 13 and is connected with the rotor shaft 11, the rotor core 12, the plurality of magnetic steel sheets 13 and the two balance blocks 14 into an integral structure, in other words, the insulating injection molding body 15 is wrapped outside the plurality of magnetic steel sheets 13 to replace a magnetic steel sleeve 17 in the prior art; or, the insulation injection molding body 15 is wrapped on the rotor core 12 and connected with the rotor shaft 11, the magnetic steel sheet 13 and the two balance blocks 14 to form an integral structure, in other words, the insulation injection molding body 15 is wrapped outside the rotor core 12 to replace a magnetic steel sleeve in the prior art, so that the insulation between the magnetic steel sheet 13 or the rotor core 12 and the stator assembly 2 in the rotor assembly 1 is improved by using the insulation effect of the injection molding insulator, the connection tightness between each component in the rotor assembly 1 can be improved by using the injection molding insulator, and the normal operation of the brushless motor is ensured; the insulating injection molding body 15 is adopted to replace the magnetic steel sleeve 17 to wrap the plurality of magnetic steel sheets 13 or the rotor core, so that the eddy current loss can be reduced in the rotating process, and the service life of the rotor assembly 1 is correspondingly ensured.

In an embodiment of the present invention, as shown in fig. 4 and 5, the inner wall of the rotor core 12 and/or the outer wall of the rotor shaft 11 are provided with a first guiding groove 121, the balance weight 14 is provided with a feeding hole 141 for injecting the insulation injection molding 15, and the feeding hole 141 is communicated with the first guiding groove 121.

It should be noted that a first guide groove 121 is disposed on an inner wall of the rotor core 12, or a first guide groove 121 is disposed on an outer wall of the rotor shaft 11, or first guide grooves 121 are disposed at corresponding positions on the inner wall of the rotor core 12 and the outer wall of the rotor shaft 11, respectively, and a feed inlet 141 is disposed on one balance weight 14, and the feed inlet 141 corresponds to and communicates with the first guide groove 121, when the insulation injection molded body 15 is injected from the feed inlet 141 by an injection molding machine and enters the first guide groove 121, at this time, the insulation injection molded body 15 is filled in the first guide groove 121 between the rotor core 12 and the rotor shaft 11, so that not only the fixing function between the rotor core 12 and the rotor shaft 11 can be achieved, but also the relative movement of the rotor core 12 with respect to the rotor shaft 11 in the axial direction and the circumferential direction can be avoided. The length of the first guide groove 121 corresponds to the axial length of the rotor core 12, so as to ensure that the insulation injection molded body 15 in the first guide groove 121 has a sufficient contact area with the rotor core 12 and the rotor shaft 11, and further ensure the connection tightness between the rotor core 12 and the rotor shaft 11.

In an embodiment of the present invention, as shown in fig. 5 and fig. 6, the number of the first guide groove 121 and the feed inlets 141 is plural, and plural the first guide groove 121 is distributed along the circumferential direction of the rotor core 12 and/or the rotor shaft 11, and plural the feed inlets 141 are distributed along the circumferential direction of the inner wall of the balance weight 14.

It should be noted that the plurality of first guide grooves 121 may be circumferentially arranged on the inner wall of the rotor core 12, or the plurality of first guide grooves 121 may be circumferentially arranged on the outer wall of the rotor shaft 11, or the inner wall of the rotor core 12 and the outer wall of the rotor shaft 11 are respectively provided with the plurality of first guide grooves 121; the number and the position of the feed inlets 141 correspond to the number and the position of the first guide grooves 121, in other words, each feed inlet 141 is respectively communicated with each first guide groove 121, so that the insulation injection molded bodies 15 can respectively enter each first guide groove 121 from each feed inlet 141 at the same time, thereby not only improving the speed of injecting the insulation injection molded bodies 15 into the first guide grooves 121 to improve the assembly efficiency of the rotor assembly 1, but also increasing the connection tightness between the rotor core 12 and the rotor shaft 11 by increasing the volume of the insulation injection molded bodies 15 in the first guide grooves 121 to further prevent the rotor core 12 from rotating axially or circumferentially relative to the rotor shaft 11.

Wherein, the first guide groove 121 corresponds to the position of the feed port 141; that is, when the plurality of first guide grooves 121 may be arranged at equal intervals, the plurality of feed ports 141 may also be arranged at equal intervals; when the plurality of first guide grooves 121 are arranged at unequal intervals, the plurality of feed ports 141 are also arranged at unequal intervals.

In an embodiment of the present invention, as shown in fig. 4, a plurality of isolation teeth 16 are disposed at intervals on the circumferential outer wall of the rotor core 12, a positioning groove is formed between two adjacent isolation teeth 16, and each of the magnetic steel sheets 13 is disposed in each of the positioning grooves.

The plurality of magnetic steel sheets 13 are circumferentially arranged on the circumferential outer wall of the rotor core 12, and the specific connection manner of the magnetic steel sheets and the rotor core is as follows: the plurality of isolation teeth 16 are arranged on the circumferential outer wall of the rotor core 12 at intervals, and a positioning groove is formed between every two adjacent isolation teeth 16, so that each magnetic steel sheet 13 is conveniently installed in each positioning groove, in other words, the positioning groove provides an installation position for installing the magnetic steel sheets 13, and the isolation effect is also achieved on every two adjacent magnetic steel sheets 13; when the number of the magnetic steel sheets 13 arranged outside the stator core 22 is four, any two adjacent magnetic steel sheets 13 are respectively defined as an N-pole magnetic steel sheet 13 and an S-pole magnetic steel sheet 13, and the N-pole magnetic steel sheet 13 and the S-pole magnetic steel sheet 13 are alternately arranged, so that the isolation teeth 16 are used for isolating the two adjacent magnetic steel sheets 13. Wherein, the size of the positioning groove is matched with the size of the magnetic steel sheet 13, so that the magnetic steel sheet 13 is smoothly placed in the positioning groove. Wherein, the isolation teeth can be of a convex rib structure.

In this embodiment, a plurality of magnetic steel sheets 13 are arranged on the circumferential outer wall of the rotor core 12 in a circumferential manner, and the insulation injection molding body 15 is wrapped on the outer portion of the plurality of magnetic steel sheets 13, so as to perform an insulation effect with the stator assembly 2, and the insulation injection molding body 15 further comprises a rotor shaft 11, the rotor core 12 and two balance blocks 14 which are connected to form an integrated structure, so that the connection and assembly among the components of the rotor assembly 1 are more tight and firm. The mounting grooves 122 are circumferentially arranged around the central axis of the rotor core 12 and are located on the outer wall of the rotor core 12.

In an embodiment of the present invention, as shown in fig. 3 and 4, the thickness of the magnetic steel sheet 13 is greater than the thickness of the isolation tooth 16, two adjacent magnetic steel sheets 13 protrude to form a gap 131 between the partial structures of the isolation tooth 16, and the insulation injection molded body 15 wraps the magnetic steel sheet 13 and fills the gap 131.

It should be noted that, the thickness of the magnetic steel sheets 13 is set to be greater than that of the isolation teeth 16, so that when each magnetic steel sheet 13 is installed in each positioning groove, a gap 131 exists between the structures of two adjacent magnetic steel sheets 13 that are higher than the isolation teeth 16, when the insulation injection molded body 15 wraps the plurality of magnetic steel sheets 13, the gap 131 is filled by the parts of the insulation injection molded body 15, and at this time, the insulation injection molded body 15 can tightly fix the plurality of magnetic steel sheets 13 outside the rotor core 12. Because a gap 131 is reserved between two adjacent magnetic steel sheets 13, a convex rib is arranged at a position, corresponding to the gap 131, on the insulating injection molded body 15 wrapped outside the magnetic steel sheets 13, and the convex rib is matched with the gap 131.

In an embodiment of the present invention, as shown in fig. 5 and fig. 6, a feeding hole 142 is disposed at one end of the balance weight 14 away from the rotor core 12, an annular flow channel 143 is disposed at one end of the balance weight 14 facing the rotor core 12, and the feeding hole 142 and each of the gaps 131 are respectively communicated with the annular flow channel 143.

It should be noted that a connecting line between the annular flow channel 143 and each gap 131 is parallel to the rotor shaft 11, in other words, the position of the annular flow channel 143 corresponds to the position of each gap 131, so as to ensure that the insulation injection molded body 15 entering the annular flow channel 143 from the feeding hole 142 can smoothly enter each gap 131; the number of the feed holes 142 may be one or more, and is not particularly limited. A feed hole 142 is provided in one of the balance weights 14 at the end facing away from the rotor core 12, an annular flow passage 143 is provided at an end of the balance weight 14 facing the rotor core 12, and the feed hole 142 and each gap 131 are respectively communicated with the annular flow passage 143, so that after the magnetic steel sheets 13 are respectively arranged in the positioning slots outside the rotor core 12, and because the two balance blocks 14 are sleeved outside the rotor shaft 11 and located at two sides of the rotor core 12, the fluid-shaped insulating injection-molded body 15 can be injected from the feeding hole 142, and then enter the annular flow passage 143 to perform annular flow, because each gap 131 is communicated with the annular flow passage respectively, the insulation injection molded bodies 15 in the annular flow passages 143 enter the gaps 131 between two adjacent magnetic steel sheets 13 respectively, and an insulation injection molding body 15 which covers or wraps the magnetic steel sheet 13 and is connected with the two balance blocks 14, and forms an annular cylindrical structure after solidification.

When the fluid-like insulation injection molding bodies 15 are respectively filled in the first guide grooves 121 between the rotor core 12 and the rotor shaft 11, the gaps 131 between the adjacent magnetic steel sheets 13 are wrapped outside the magnetic steel sheets 13 and connected with the two balance blocks 14, and after solidification, the rotor shaft 11, the rotor core 12, the magnetic steel sheets 13 and the two balance blocks 14 form an integrated structure, so that the assembling tightness and the insulating property of each component of the rotor assembly 1 are ensured.

In an embodiment of the present invention, a plurality of mounting grooves 122 are disposed between the inner wall and the outer wall of the rotor core 12, and each of the magnetic steel sheets 13 is embedded in each of the mounting grooves 122.

It should be noted that, referring to fig. 12 and 13, the rotor core 12 and the magnetic steel sheets 13 further have a connection manner different from the above structure, for example, a plurality of magnetic steel sheets 13 are arranged in a circumferential manner inside the rotor core 12, wherein a plurality of mounting slots 122 are formed between the inner wall and the outer wall of the rotor core 12, the number and size of the mounting slots 122 are matched with the number and size of the magnetic steel sheets 13, so that each magnetic steel sheet 13 is respectively embedded in each mounting slot 122, in other words, the mounting slots 122 provide a mounting space or position for the magnetic steel sheets 13, at this time, the insulation injection molded body 15 wraps the outside of the rotor core 12, so as to play an insulation role with the stator assembly 2, and the insulation injection molded body 15 is further connected with the rotor shaft 11, the magnetic steel sheets 13 and the two balance blocks 14 to form an integral structure, so that the connection assembly between the components of the rotor assembly 1 is more compact and firm. Wherein the plurality of mounting grooves 122 are circumferentially arranged around the central axis of the rotor core 12.

In an embodiment of the present invention, as shown in fig. 9 and fig. 11, the stator assembly 2 includes a coil frame body 21, a stator core 22, a stator winding 23 and a plurality of insulation seats 24, a plurality of channels are provided in the stator core 22 and distributed along the circumferential direction thereof, and each of the insulation seats 24 is distributed and embedded in each of the channels, the coil frame body 21 is disposed at an axial end of the stator core 22, and a threading opening 211 is provided on the coil frame body 21 for the stator winding 23 to pass through.

It should be noted that, a plurality of slots are arranged in the stator core 22, and the plurality of slots are distributed at intervals along the circumferential direction of the stator core 22, each insulating seat 24 is installed in each slot, the insulating seat 24 is used for installing the stator winding 23, when the stator winding 23 is wound in the stator core 22, the middle part of the insulating seat 24 is located in the insulating seat, so that the insulating function between the stator winding 23 and the stator core 22 can be achieved through the insulating seat 24; the number of the coil frame bodies 21 may be two, and the two coil frame bodies 21 are respectively installed at two axial ends of the stator core 22, a threading opening 211 is formed in the coil frame body 21, when the stator winding 23 is wound in the stator core 22, the stator winding 23 can smoothly pass through the threading opening 211 in the coil frame body 21, wherein an end structure in the stator winding 23 is located on the coil frame body 21, in other words, the insulating base 24 and the coil frame body 21 can form an insulating layer on a winding path of the stator winding 23, so as to enhance insulation between the stator coil and the stator core 22. The number of the insulating holders 24 may be six, and may be other numbers, which are specifically related to the kinds of the brushless motors and are not specifically limited herein.

In an embodiment of the present invention, as shown in fig. 9 to 11, the inner wall of the threading opening 211 is provided with a sealing rib 212, a partial structure of the insulating base 24 extends out of the channel, and a partial structure of the insulating base 24 is inserted into the threading opening 211 and is abutted against the sealing rib 212.

It should be noted that, in a general case, when a brushless motor in an electric tool performs operations such as cutting, polishing, drilling, etc., a certain amount of metal particles are generated, and at this time, the metal particles easily enter the stator assembly 2 from an air inlet of the brushless motor, and because the insulating base 24 is embedded and installed in the slot, a certain gap exists between the insulating base 24 and the slot, and the metal particles enter the gap between the insulating base 24 and the slot, which causes the insulating function of the insulating base 24 to fail, thereby causing the operation failure of the brushless motor. Therefore, by arranging the sealing rib 212 on the inner wall of the threading opening 211 of the coil frame body 21, when the coil frame body 21 is installed at the end of the stator core 22, the part of the structure of the insulating base 24 extending out of the channel is embedded in the threading opening 211 and abuts against the sealing rib 212, and at this time, the sealing rib 212 not only can play a role in positioning the insulating base 24 to prevent the insulating base 24 from sliding relative to the coil frame body 21, but also can form a stop for metal particles, so that the difficulty of the metal particles entering a gap between the insulating base 24 and the inner wall of the channel is increased, and the sealing effect between the insulating base 24 and the inner wall of the channel is improved; in addition, because partial structures of the insulation seats 24 extend out of the slots, when the coil frame body 21 is installed at the end of the stator core 22, partial structures of the insulation seats 24 are embedded into the threading ports 211 to play a certain guiding and positioning role, so that the coil frame body 21 can be accurately installed at the end of the stator core 22. The sealing rib 212 may be any one of a sealant, a rubber sealing ring or a silica gel sealing ring, or may be a rib made of other materials, and the shape of the sealing rib 212 matches the shape of the insulating base 24, so as to ensure that the sealing rib 212 can completely seal the gap between the insulating base 24 and the channel.

In an embodiment of the present invention, as shown in fig. 10, a notch is formed on the channel, an opening 241 is formed at a position on the insulating base 24 corresponding to the notch, and a protrusion 242 for increasing an insulation distance between the stator winding 23 and the notch is formed at the opening 241 of the insulating base 24.

It should be noted that, a notch is formed at a position facing the central axis of the stator core 22 on the slot, and an opening 241 is formed at a position corresponding to the notch on the insulating base 24, so that when the stator winding 23 is wound on the insulating base 24 and the coil frame body 21 on the stator core 22, the stator winding 23 is effectively avoided so as to be smoothly and rapidly wound on the insulating base 24 and the coil frame body 21, and a certain heat dissipation effect can be performed on the stator winding 23 in the insulating base 24. By providing the protrusion 242 for increasing the insulation distance between the stator winding 23 and the slot at the opening 241 of the insulation seat 24, when a part of the structure of the stator winding 23, such as the middle portion, is located in the insulation seat 24, the protrusion 242 can increase the insulation distance between the stator winding 23 and the slot, so that the insulation between the stator core 22 and the stator winding 23 can be enhanced, and the normal operation of the stator assembly 2 can be ensured.

The embodiment of the utility model provides an electric tool is still provided, including as above embodiment brushless motor.

It should be noted that, the electric tool further includes a motor housing, and the brushless motor is disposed in the motor housing to generate a certain protection for the brushless motor. The electric tool can be a handheld angle grinder, a handheld cutting machine, a handheld electric scissors or other types of electric tools, and the electric tools which can use the brushless motor are all suitable for the technical scheme and are not specifically limited.

Although the present disclosure has been described above, the scope of the present disclosure is not limited thereto. Various changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the present disclosure, and these changes and modifications are intended to fall within the scope of the present disclosure.

Claims

1. A brushless motor comprises a rotor assembly (1) and a stator assembly (2) sleeved outside the rotor assembly (1), and is characterized in that the rotor assembly (1) comprises a rotor shaft (11), a rotor core (12), a plurality of magnetic steel sheets (13), two balance blocks (14) and an insulation injection molding body (15), the rotor core (12) is sleeved outside the rotor shaft (11), the two balance blocks (14) are sleeved on the rotor shaft (11) at intervals and located on two opposite sides of the rotor core (12), the plurality of magnetic steel sheets (13) are arranged at the position of the rotor core (12) in a circumferential mode, the insulation injection molding body (15) wraps the plurality of magnetic steel sheets (13) and is connected with the rotor shaft (11), the rotor core (12) and the two balance blocks (14) to form an integral structure, or the insulation injection molding body (15) is wrapped on the rotor iron core (12) and is connected with the rotor shaft (11), the magnetic steel sheet (13) and the two balance blocks (14) to form an integral structure.

2. The brushless electric machine according to claim 1, wherein the inner wall of the rotor core (12) and/or the outer wall of the rotor shaft (11) is provided with a first guide groove (121), the balance weight (14) is provided with a feed opening (141) for facilitating injection of the insulation injection molded body (15), and the feed opening (141) is communicated with the first guide groove (121).

3. The brushless electric machine according to claim 2, wherein the number of the first guide grooves (121) and the number of the feed openings (141) are plural, and the plural first guide grooves (121) are distributed along a circumferential direction of the rotor core (12) and/or the rotor shaft (11), and the plural feed openings (141) are distributed along a circumferential direction of an inner wall of the weight (14).

4. The brushless motor according to claim 1, wherein a plurality of isolation teeth (16) are spaced apart from each other on the circumferential outer wall of the rotor core (12), a positioning groove is formed between two adjacent isolation teeth (16), and each magnetic steel sheet (13) is disposed in each positioning groove.

5. The brushless motor according to claim 4, wherein the thickness of the magnetic steel sheets (13) is greater than that of the isolation teeth (16), a gap (131) is formed between the partial structures of two adjacent magnetic steel sheets (13) protruding out of the isolation teeth (16), and the insulation injection molded body (15) wraps the magnetic steel sheets (13) and fills the gap (131).

6. The brushless electric machine according to claim 5, wherein a feed hole (142) is provided at an end of the weight (14) facing away from the rotor core (12), an annular flow channel (143) is provided at an end of the weight (14) facing toward the rotor core (12), and the feed hole (142) and each of the gaps (131) communicate with the annular flow channel (143), respectively.

7. The brushless motor according to claim 1, wherein a plurality of mounting grooves (122) are formed in an annular arrangement between an inner wall and an outer wall of the rotor core (12), and the magnetic steel sheets (13) are respectively embedded in the mounting grooves (122).

8. The brushless motor according to any one of claims 1 to 7, wherein the stator assembly (2) includes a coil frame body (21), a stator core (22), a stator winding (23), and a plurality of insulation seats (24), a plurality of channels are disposed in the stator core (22) along a circumferential direction of the stator core, each insulation seat (24) is disposed in each channel in an embedded manner, the coil frame body (21) is disposed at an axial end portion of the stator core (22), and a threading opening (211) for the stator winding (23) to pass through is disposed on the coil frame body (21).

9. The brushless motor according to claim 8, wherein a sealing rib (212) is arranged on an inner wall of the threading opening (211), a part of structure of the insulation seat (24) extends out of the channel, and a part of structure of the insulation seat (24) is arranged in the threading opening (211) in a penetrating manner and is abutted against the sealing rib (212).

10. The brushless motor according to claim 8, wherein the slot is provided with a notch, the insulating base (24) is provided with an opening (241) at a position corresponding to the notch, and the insulating base (24) is provided with a protrusion (242) at the opening (241) for increasing an insulating distance between the stator winding (23) and the notch.

11. A power tool comprising a brushless motor according to any one of claims 1 to 10.