CN206153618U - Electric tool - Google Patents

Abstract

The utility model provides an electric tool, including the main part and with the main part rotates the working head of connecting, install single -phase brushless motor in the main part, the working head can the quilt single -phase brushless motor drives and two -way rotation. Implement the utility model discloses, electric tool's volume and cost can effectively reduce.

Description

Electric tool

【Technical field】

The utility model is related to a kind of electric tool.

【Background technology】

In prior art, electric tool such as electric drill uses general-purpose machine, this kind of motor volume is big, weight is big, around Group number of coils is big.Motor is used as the critical piece of electric drill, and the overall volume of its volume, weight and electric drill, weight are closely bound up. Using the electric tool volume of general-purpose machine is big, weight big, its cost is also larger.

【Utility model content】

The purpose of this utility model is to provide the electric tool of a kind of small volume, low cost.

A kind of electric tool, including main part and the work head that is connected is rotated with the main part, in the main part Brushless single phase motor is installed, the work head can by the brushless single phase Motor drive Double-directional rotary.

Used as a kind of preferred version, the twocouese startup ability of the brushless single phase motor is identical.

Used as a kind of preferred version, the brushless single phase motor includes stator and rotor, and the stator includes stator core And the stator winding being set around on stator core, if the stator core includes outer yoke portion, extends inwardly from the outer yoke portion Dry stator tooth, the radial inner end face of each stator tooth is recessed the cambered surface relative with rotor, the circumferential center tool of each cambered surface There is a detent, each detent is located on the center line of correspondence stator tooth, and the cambered surface of some stator tooths is enclosed jointly Into a host cavity, the rotor is contained in the host cavity that the cambered surface is surrounded.

Used as a kind of preferred version, the twocouese of the brushless single phase motor starts ability difference.

Used as a kind of preferred version, the brushless single phase motor includes stator and rotor, and the stator includes stator core And the stator winding being set around on stator core, if the stator core includes outer yoke portion, extends inwardly from the outer yoke portion Dry stator tooth, the radial inner end face of each stator tooth is recessed the cambered surface relative with rotor, and each cambered surface has a positioning recessed Groove, each detent deviates the center line of correspondence stator tooth, and the cambered surface of some stator tooths surrounds a host cavity jointly, The rotor is contained in the host cavity that the cambered surface is surrounded.

Used as a kind of preferred version, the brushless single phase motor includes stator and rotor, and the stator includes stator core And the stator winding being set around on stator core, if the stator core includes outer yoke portion, extends inwardly from the outer yoke portion Dry stator tooth, the radial inner end face of each stator tooth is recessed the cambered surface relative with rotor, and the circumferential center of each cambered surface is inclined From the center of correspondence stator tooth, the cambered surface of some stator tooths surrounds a host cavity jointly, and the rotor is contained in the arc In the host cavity that face surrounds.

Used as a kind of preferred version, each cambered surface has a detent, and each detent is located at correspondence stator tooth On center line.

Used as a kind of preferred version, the brushless single phase motor includes stator and rotor, and the stator includes stator core And the stator winding being set around on stator core, if the stator core includes outer yoke portion, extends inwardly from the outer yoke portion Dry stator tooth, the radial inner end face of each stator tooth is recessed the cambered surface relative with rotor, the cambered surface of some stator tooths A host cavity is surrounded jointly, and the rotor is contained in the host cavity that the cambered surface is surrounded, between the rotor and the cambered surface Form substantially homogeneous air gap.

As a kind of preferred version, disconnected by slotting between adjacent stators tooth, the width of the fluting is less than or equal to institute State even air gap thickness 3 times.

Used as a kind of preferred version, the brushless single phase motor includes stator and rotor, and the stator includes stator core And the stator winding being set around on stator core, if the stator core includes outer yoke portion, extends inwardly from the outer yoke portion Dry stator tooth, the radial inner end face of each stator tooth is recessed the cambered surface relative with rotor, the cambered surface of some stator tooths A host cavity is surrounded jointly, and the rotor is contained in the host cavity that the cambered surface is surrounded, between the rotor and the cambered surface Form symmetrical non-homogeneous air gap.

As a kind of preferred version, disconnected by slotting between adjacent stators tooth, the width of the fluting is less than or equal to institute State the symmetrically minimum thickness of non-homogeneous air gap 4 times.

As a kind of preferred version, between adjacent stators tooth by magnetic bridge connection or by slot disconnect, the magnetic bridge or Line between the center and the rotor center of circle of fluting forms the angle of 60 to 90 degree with the bearing of trend of a wherein stator tooth.

Used as a kind of preferred version, the stator core includes two the first stators being oppositely arranged along root diameter direction Tooth and the second stator tooth, the radial inner end face of the first stator tooth is recessed the first cambered surface, the radial inner end face of the second stator tooth The second cambered surface is recessed, the circumferential two ends of first cambered surface form respectively the first tangent plane and the second tangent plane, second arc The circumferential two ends in face form respectively the 3rd tangent plane and the 4th tangent plane；First tangent plane is relative with the 3rd tangent plane and mutual Every so as to form the first fluting, second tangent plane is relative with the 4th tangent plane and spaced so as to form the second fluting, The bearing of trend of first tangent plane, the second tangent plane, the 3rd tangent plane and the 4th tangent plane relative stator tooth is inclined or vertical.

Used as a kind of preferred version, the electric tool is electric drill.

Used as a kind of preferred version, the circumferential width of the stator tooth is 0.8 to 1.6 times of the rotor diameter.

Used as a kind of preferred version, the radial thickness in the outer yoke portion is 0.3 to 0.7 times of rotor diameter.

Implement the utility model, the volume and cost of electric tool can be reduced effectively.

【Description of the drawings】

Below in conjunction with Figure of description and embodiment, the utility model is described in further detail.

Fig. 1 is the structural representation of the utility model electric tool.

Fig. 2 is the overall structure diagram of the monophase machine of an embodiment of the utility model electric tool.

Fig. 3 is the sectional view of monophase machine shown in Fig. 2.

Fig. 4 is the top view of the stator core of monophase machine shown in Fig. 2 and rotor.

Fig. 5 is the rotor exploded perspective view of monophase machine shown in Fig. 2.

Fig. 6 is the stator core of monophase machine shown in Fig. 2 and the first fixed support, the second support bracket fastened structural representation Figure.

Fig. 7 is the structural representation of the insulating frame of monophase machine shown in Fig. 2 and winding.

Fig. 8 is the stator core of the one-way motors of another embodiment of the utility model electric tool, stator winding and turns The top view of son.

Fig. 9 is the schematic diagram of the stator core that monophase machine shown in Fig. 8 is used.

Figure 10 is the vertical view of the stator core with rotor of the one-way motors of the another embodiment of the utility model electric tool Figure.

【Specific embodiment】

Fig. 1 is a kind of schematic diagram of embodiment of electric tool of the present utility model 200.In the present embodiment, this is electronic Instrument 200 is electric drill.The electric tool 200 includes main body 210 and work 220, and 210 are provided with motor for driving in main body Start building to make 220 motion.

Fig. 2 is refer to, is the motor 30 of an embodiment of the utility model electric tool 200.The motor 30 is one single-phase Motor.In the present embodiment, the monophase machine is brushless single phase motor.In other embodiments, the motor 30 is alternatively single Phase permagnetic synchronous motor.

Referring to Fig. 2 to Fig. 5, in the present embodiment, motor 30 includes stator and rotor, and rotor includes rotating shaft 61, consolidates Determine to the rotor magnetic core 62 in rotating shaft 61 and the permanent magnet 63 being fixed on rotor magnetic core 62.Wherein, permanent magnet 63 is monoblock type Annular permanent magnets.It is to be appreciated that permanent magnet 63 can be some pieces of magnets；Permanent magnet 63 can also be affixed directly to rotating shaft 61 On.Preferably, the radial thickness D2 of permanent magnet 63 is 0.2 to 0.24 times of rotor diameter D1.

Stator includes stator core 41 and around the winding 49 being located on stator core 41；Stator core 41 includes outer yoke portion 50th, some stator tooths 52,56 extended inwardly from outer yoke portion 50.In the specification and claims, will be perpendicular to stator tooth The size of bearing of trend be referred to as the width of the stator tooth, outer yoke portion 50 is referred to as into the thickness in outer yoke portion 50 along the size of stator radial direction Degree.In the present embodiment, the width W1 of the first stator tooth 52 and the second stator tooth 56 is 0.8 to 1.6 times of rotor diameter D1.Outer yoke Portion 50 is frame shape, and the radial thickness W2 in outer yoke portion 50 is 0.3 to 0.7 times of rotor diameter D1.

The radial inner end face of each stator tooth includes the cambered surface relative with rotor；Specifically, the end face of the first stator tooth 52 First cambered surface 52a relative with rotor is recessed, the end face of the second stator tooth 56 is recessed second arc relative with rotor Face 56a.First cambered surface 52a is relative with the second cambered surface 56a, and forms host cavity between the two, and permanent magnet 63 is contained in the receipts In cavity volume.

The first of larger magnetic resistance is formed between first stator tooth 52 and the second stator tooth 56 in the outside of permanent magnet 63 respectively to open The fluting of groove 53 and second 54.More specifically, the circumferential two ends of the first cambered surface 52a form respectively the first tangent plane 52c and second and cut Face 52d；The circumferential two ends of the second cambered surface 56a form respectively the 3rd tangent plane 56c and the 4th tangent plane 56d, the first tangent plane 52c and the 3rd The first fluting 53 is formed between tangent plane 56c；Second tangent plane 52d is relative with the 4th tangent plane 56d to form therebetween the second fluting 54.Preferably, the first fluting 53 and the second fluting 54 are basically the same, and with regard to the center of rotation of rotor symmetrical.First The bearing of trend shape of line and a wherein stator tooth 52 or 56 between the center and the rotor center of circle of the fluting 54 of fluting 53 and second Into the angle of 60 to 90 degree, in the present embodiment, the angle of formation is 90 degree, i.e., the center of the first fluting 53 and the second fluting 54 Between line through rotor center of rotation, it is vertical with the bearing of trend of stator tooth 52 or 56.For forming the first fluting 53 The first tangent plane 52c, the 3rd tangent plane 56c or for formed second fluting 54 the second tangent plane 52d, the 4th tangent plane 56d it is relatively fixed The bearing of trend of sub- tooth 52,56 is vertical.

First stator tooth 52 also includes the first detent 52b being arranged in the first cambered surface 52a, and the second stator tooth 56 is also Including the second detent 56b being arranged in the second cambered surface 56a.First detent 52b and the second detent 56b edges turn The diametrically opposite setting of son, rotor is positioned recessed relative to the position of stator by adjustment when stopping for controlled motor 30 The stop position or initial position of the adjustable rotor in the position of groove 52b, 56b.The channel opening of above-mentioned first locating slot 52b is towards forever Magnet 63, the channel opening of the second locating slot 56b is towards permanent magnet 63.The company of the first detent 52b, the second detent 56b Line direction overlaps with the center line of the first stator tooth 52, the second stator tooth 56.Thus, motor has two-way startup ability, and two The staring torque in individual direction is of substantially equal.In other embodiments, the center line of the positional deviation stator tooth of detent can be made, Make rotor two-way startup torque different.

Preferably, the first cambered surface 52a and the second cambered surface 56a are located on the same face of cylinder, along cylinder EDS maps, the circle The central shaft of cylinder is coaxial with the center of rotation of rotor, so as to the rotor outer surface and first of permanent-magnet pole formed in permanent magnet 63 Substantially homogeneous air gap 65 is formed between cambered surface 52a and the second cambered surface 56a and (removes detent 52b, 56b, fluting 53,54 and phase The region outside differential gap between adjacent permanent-magnet pole is elsewhere even air gap), and the first fluting 53 and the second fluting 54 Edge is less than or equal to 3 times of the thickness of above-mentioned even air gap 65 perpendicular to the width of the bearing of trend of stator tooth 52,56.The present embodiment In, cambered surface 52a relative with rotor of stator tooth 52 is evenly distributed on the both sides of the symmetrical center line of stator tooth 52, stator tooth 56 Cambered surface 56a relative with rotor be evenly distributed on stator tooth 56 symmetrical center line both sides that is, cambered surface 52a and arc It is equal that face 56a is located at stator tooth 52, the circumferential lengths of the part of 56 center lines circumference both sides.

Fig. 2, Fig. 3, Fig. 6 and Fig. 7 are please also refer to, stator winding 49 is installed to the He of the first stator tooth 52 of stator core 41 Second stator tooth 56, stator winding 49 can produce two magnetic loops by rotor when being powered.The stator tooth of stator core 41 52nd, set between 56 and stator winding 49 insulation coil holder 47, as shown in fig. 6, insulation coil holder 47 include two the first insulation divisions 36 with And the second insulation division 37 between two the first insulation divisions 36.This two the first insulation divisions 36 are respectively used to cover stator magnet Two stator tooths 52,56 of core 41, second insulation division 37 is used for the outer weekly form of cambered surface 52a, 56a for covering stator tooth 52,56 Face.Two winding baffle plates 38 are respectively arranged at two ends with per one first insulation division 36, corresponding winding 49 is located at two winding gears Between plate 38.In the present embodiment, insulation coil holder 47 is axially spaced into upper and lower two parts along motor 30.The top of the second insulation division 37 Face is higher than the main part of the first insulation division 36, and the bottom surface of the second insulation division 37 protrudes from the main part of the first insulation division 36, For example maintain an equal level with the height of winding baffle plate 38.The top surface of the second insulation division 37 is provided with the first opening 57 of first direction, Bottom surface is provided with the second opening 58 of second direction；First direction differs 180 ° with second direction.Above-mentioned first opening 57, the Two openings 58 can be used for installing Hall element.

In the present embodiment, the outer yoke portion 50 of the frame shape can be formed by the chip stack of integral type.Certainly, in the utility model Other embodiment in, the outer yoke portion 50 of the frame shape can also be made up of the first half yoke portions with the second half yoke portion splicings.

As shown in fig. 6, in the present embodiment, stator also includes axially setting up separately the first of the both sides of stator core 41 along motor 30 The fixed support 23 of fixed support 21 and second.First fixed support 21 is provided with the first hub portion 22 is used to installing bearing 42, and first Rotating shaft 61 is installed and supported by bearing 42 in hub portion 22.Similarly, the second fixed support 23 is provided with the second hub portion 24, the second hub Rotating shaft 61 is installed and supported by bearing 44 in portion 24.Thus, rotor can by the first fixed support 21 and the second fixed support 23 It is pivotally mounted to stator.In the present embodiment, the first fixed support 21 is in " several " font, and its two ends is provided with first through hole 27；The Two fixed supports 23 are also in " several " font, and its two ends is provided with the second through hole 28；Along motor shaft in the outer yoke portion 50 of stator core 41 To being provided with third through-hole 29.Bolt 48 sequentially pass through the end of the first fixed support 21, the outer yoke portion 50 of stator core 41, The end of the second fixed support 23 is fixedly installed togather the first fixed support 21, the second fixed support 23, stator core 41.

In the present embodiment, each end of the first fixed support 21 is additionally provided with the first kink 62, and the first kink 66 has There is the bending for being similar to right angle to be used to be close to the outer edge of yoke portion 50 of the stator core 41；Similarly, the second fixed support 29 Each end also be provided with the second kink 64, the second kink 64 is same have the bending for being similar to right angle be used to being close to it is described The outer edge of yoke portion 50 of stator core 41.

Fig. 8, Fig. 9 are refer to, in the brushless single phase motor of another embodiment offer of the utility model electric tool 200 Stator core 41 is made up of the first half core and the second half core, and the first half core and the second half core are provided with mutually on both faying faces The concavo-convex retaining structure for coordinating.First half core includes the first half yoke portions 51 and first determines from what the first half yoke Bu51Chao centers were stretched out Sub- tooth 52, the second stator tooth 56 that the second half core includes the second half yoke portions 55 and stretches out from the second half yoke Bu55Chao centers, first Half yoke portion 51 and the second half yoke portions 55 collectively constitute outer yoke portion 50, and in the present embodiment, outer yoke portion 50 is rounded.First stator tooth 52 and second in the outside of permanent magnet 63 form first fluting 53 and the second fluting 54 of larger magnetic resistance between stator tooth 56 respectively.This In embodiment, the width W1 of the first stator tooth 52 and the second stator tooth 56 can be 0.8 to 1.6 times of rotor diameter D1；Outer yoke The thickness W2 in portion 50 can be 0.3 to 0.7 times of rotor diameter D1.First stator tooth 52 includes the first cambered surface 52a, the first cambered surface 52a has the first detent 52b；Second stator tooth 56 includes the second cambered surface 56a, and the second cambered surface 56a has the second positioning recessed Groove 56b.First detent 52b and the second detent 56b stop along the diametrically opposite setting of rotor for controlled motor When only rotor relative to stator position, by the stop position of the adjustable rotor in the position for adjusting detent 52b, 56b or Initial position.First cambered surface 52a is relative with the second cambered surface 56a, and forms host cavity between the two, and permanent magnet 63 is contained in this In host cavity.Preferably, the first cambered surface 52a and the second cambered surface 56a are along cylinder EDS maps, and the face of cylinder is coaxial with rotor, from And form substantially homogeneous between the outer surface and the first cambered surface 52a and the second cambered surface 56a of the permanent-magnet pole that permanent magnet 63 is formed Air gap 65 (removes detent 52b, 56b, outside the fluting 53, differential gap between 54 and adjacent permanent magnetic poles is elsewhere equal Even air gap).

Fig. 9 is referred to, more specifically, the circumferential two ends of the first cambered surface 52a form respectively the first tangent plane 52c and second and cut Face 52d；The circumferential two ends of the second cambered surface 56a form respectively the 3rd tangent plane 56c and the 4th tangent plane 56d, the first tangent plane 52c and the 3rd First fluting 53 is formed between tangent plane 56c；Second tangent plane 52d is relative with the 4th tangent plane 56d to form therebetween described Second fluting 54.

The distance between first tangent plane 52c and the 3rd tangent plane 56c is 0.09 to 0.13 times of rotor diameter D1；Second tangent plane The distance between 52d and the 4th tangent plane 56d are also 0.09 to 0.13 times of rotor diameter D1.

Preferably, the first fluting 53 and the second fluting 54 are basically the same, and with regard to the center of rotation of rotor symmetrical. First fluting 53 and second fluting 54 centers between line L1 through rotor center of rotation, the extension with the first stator tooth 52 Direction L2 forms the angle Q of 60 to 90 degree, and more preferred scheme is, the company between the first fluting 53 and the second 54 centers of fluting The bearing of trend of line and the second stator tooth 56 forms the angle of 60 to 65 degree.

, towards permanent magnet 63, the channel opening of the second locating slot 56b is towards permanent magnet 63 for the channel opening of the first locating slot 52b. The width of the channel opening of the first locating slot 52b and the second locating slot 56b is 0.24 to 0.28 times of rotor diameter D1, and the groove is opened The width of mouth refers to the first locating slot 52b and the second locating slot 56b along the circumferential size of permanent magnet.First detent 52b, The line direction of two detent 56b overlaps with the center line of the first stator tooth 52, the second stator tooth 56.In the present embodiment, the One detent 52b deviates the circumferential center of the first cambered surface 52a, and the second detent 56b deviates in the circumference of the first cambered surface 56a The heart, therefore, the motor 30 is unequal in the staring torque of both direction, and this kind of motor is particularly suited for wanting different rotation directions Ask the application scenario of different driving torque, such as electric drill, electric screw driver etc..

Figure 10 is refer to, the brushless single phase motor 30 that the another embodiment of the utility model electric tool 200 is provided includes Stator 70 and can relative stator 70 rotate rotor 80.Rotor 80 includes rotating shaft 81, the rotor magnetic core 82 being fixed in rotating shaft 81 And the permanent magnet 83 being fixed on rotor magnetic core 82.Stator 70 include stator core and and the stator that is set around on stator core around Group (not shown).Stator core includes outer yoke portion 71 and at least two stator tooths 72 extended inwardly from outer yoke portion 71.Stator tooth 72 can set along the circumferentially-spaced distribution in outer yoke portion 71, the quantity of stator tooth 72 according to actual conditions.The end tool of stator tooth 72 Have crown 74, stator winding is set around stator core, be such as set around stator tooth 72 tooth body (be located at outer yoke portion 71 and crown 74 it Between) on.Crown 74 includes the first pole shoe 75 and the second pole shoe 76 for extending to both sides respectively.The length of the second pole shoe 76 is more than the The length of one pole shoe 75.First pole shoe 75 of each crown 74 and the inner side of the second pole shoe 76 form cambered surface towards rotor.Therefore, The center line of the circumferential center deviation correspondence stator tooth 72 of cambered surface, the startup ability in one direction of rotor 80 is more than towards another The startup ability in direction.Preferably, the cambered surface of the crown 74 is located on the same face of cylinder with the center of rotor 80 as the center of circle, The outer peripheral face of permanent magnet 83 is located on another face of cylinder with the center of rotor 80 as the center of circle, i.e. the first pole shoe 75 and the second pole shoe 76 cambered surface is concentric with the outer peripheral face of permanent magnet 83, so as between the first pole shoe 75 and the cambered surface and permanent magnet 83 of the second pole shoe 76 The air gap 85 of uniform thickness is formed, vibration and noise is reduced, motor rotation can be caused more steady, enhance startup stable Property.

In the present embodiment, the cambered surface of the inner side of the first pole shoe 75 of each crown 74 and the second pole shoe 76 is formed with one Towards the detent 77 of rotor 80, detent 77 is centrally located on the center line of correspondence stator tooth 72, i.e. detent The center of the cambered surface of 77 crowns 74 for deviateing stator tooth 72.The control that is provided for of detent 77 and asymmetric pole shoe turns The stop position namely initial position of son 80 deviates dead-centre position.

In the present embodiment, at least two stator tooths 72, the second pole shoe 76 of one of stator tooth 72 and another First pole shoe 75 of stator tooth 72 it is adjacent and between there is notch 79, there is notch 79 larger magnetic resistance to prevent the both sides of notch 79 The second pole shoe 76, the first pole shoe 75 between leakage field and the location torque of motor can be increased.It is to be appreciated that magnetic can be used The larger magnetic bridge of resistance replaces notch 79.Because the first pole shoe 75 is different from the length of the second pole shoe 76, therefore, the magnetic bridge of notch 79/ Position will deviate from one of stator tooth 72, rather than positioned at the centre position of two stator tooths 72.

In other embodiments, can also make to be formed between the first pole shoe 75 and the cambered surface and permanent magnet 83 of the second pole shoe 76 The air gap of symmetrical non-uniform thickness, so as to adjust the waveform of location torque, makes the waveform sineization of location torque so that motor Operating is more steady, lower noise.

The monophase machine of the utility model electric tool, compact conformation, the more conventional motor of its volume has and significantly subtracts It is little；The more conventional motor of weight there has also been significant reduction；Rotor is using permanent magnet so as to reducing winding amount of copper consuming, its cost Also decrease, so that electric tool 200 is lighter, compact and reduce cost.

For the person of ordinary skill of the art, without departing from the concept of the premise utility, can also do Go out some deformations and improvement, these belong to protection domain of the present utility model.Therefore, the protection domain of the utility model patent Should be defined by claims.

Claims (16)

1. a kind of electric tool, including main part and the work head being connected with main part rotation, it is characterised in that described Brushless single phase motor is installed in main part, the work head can by the brushless single phase Motor drive Double-directional rotary.

2. electric tool as claimed in claim 1, it is characterised in that the twocouese of the brushless single phase motor starts ability phase Together.

3. electric tool as claimed in claim 2, it is characterised in that the brushless single phase motor includes stator and rotor, institute Stator is stated including stator core and the stator winding that is set around on stator core, the stator core includes outer yoke portion, from described Some stator tooths that outer yoke portion extends inwardly, the radial inner end face of each stator tooth is recessed the cambered surface relative with rotor, often The circumferential center of one cambered surface has a detent, and each detent is located on the center line of correspondence stator tooth, described some The cambered surface of stator tooth surrounds a host cavity jointly, and the rotor is contained in the host cavity that the cambered surface is surrounded.

4. electric tool as claimed in claim 1, it is characterised in that the twocouese of the brushless single phase motor starts ability not Together.

5. electric tool as claimed in claim 4, it is characterised in that the brushless single phase motor includes stator and rotor, institute Stator is stated including stator core and the stator winding that is set around on stator core, the stator core includes outer yoke portion, from described Some stator tooths that outer yoke portion extends inwardly, the radial inner end face of each stator tooth is recessed the cambered surface relative with rotor, often One cambered surface has a detent, and each detent deviates the center line of correspondence stator tooth, the cambered surface of some stator tooths A host cavity is surrounded jointly, and the rotor is contained in the host cavity that the cambered surface is surrounded.

6. electric tool as claimed in claim 4, it is characterised in that the brushless single phase motor includes stator and rotor, institute Stator is stated including stator core and the stator winding that is set around on stator core, the stator core includes outer yoke portion, from described Some stator tooths that outer yoke portion extends inwardly, the radial inner end face of each stator tooth is recessed the cambered surface relative with rotor, often The center of the circumferential center deviation correspondence stator tooth of one cambered surface, the cambered surface of some stator tooths surrounds a host cavity, institute jointly State rotor to be contained in the host cavity that the cambered surface is surrounded.

7. electric tool as claimed in claim 6, it is characterised in that each cambered surface has a detent, each positioning is recessed Groove is located on the center line of correspondence stator tooth.

8. electric tool as claimed in claim 1, it is characterised in that the brushless single phase motor includes stator and rotor, institute Stator is stated including stator core and the stator winding that is set around on stator core, the stator core includes outer yoke portion, from described Some stator tooths that outer yoke portion extends inwardly, the radial inner end face of each stator tooth is recessed the cambered surface relative with rotor, institute The cambered surface for stating some stator tooths surrounds a host cavity jointly, and the rotor is contained in the host cavity that the cambered surface is surrounded, described Substantially homogeneous air gap is formed between rotor and the cambered surface.

9. electric tool as claimed in claim 8, it is characterised in that disconnected by slotting between adjacent stators tooth, it is described to open The width of groove is less than or equal to 3 times of the even air gap thickness.

10. electric tool as claimed in claim 1, it is characterised in that the brushless single phase motor includes stator and rotor, institute Stator is stated including stator core and the stator winding that is set around on stator core, the stator core includes outer yoke portion, from described Some stator tooths that outer yoke portion extends inwardly, the radial inner end face of each stator tooth is recessed the cambered surface relative with rotor, institute The cambered surface for stating some stator tooths surrounds a host cavity jointly, and the rotor is contained in the host cavity that the cambered surface is surrounded, described Symmetrical non-homogeneous air gap is formed between rotor and the cambered surface.

11. electric tools as claimed in claim 10, it is characterised in that disconnected by slotting between adjacent stators tooth, it is described The width of fluting is less than or equal to 4 times of the minimum thickness of the symmetrical non-homogeneous air gap.

12. electric tools as described in any one in claim 3,5-11 items, it is characterised in that lead between adjacent stators tooth Cross magnetic bridge connection or by disconnection of slotting, the line between the magnetic bridge or the center and the rotor center of circle of fluting and a wherein stator The bearing of trend of tooth forms the angle of 60 to 90 degree.

13. electric tools as claimed in claim 1, it is characterised in that the brushless single phase motor includes stator and rotor, institute Stator is stated including stator core and the stator winding being set around on stator core, the stator core includes two along root diameter The first stator tooth and the second stator tooth that direction is oppositely arranged, the radial inner end face of the first stator tooth is recessed the first cambered surface, The radial inner end face of the second stator tooth is recessed the second cambered surface, and the circumferential two ends of first cambered surface form respectively the first tangent plane With the second tangent plane, the circumferential two ends of second cambered surface form respectively the 3rd tangent plane and the 4th tangent plane；First tangent plane and institute State the 3rd tangent plane relative and spaced so as to form the first fluting, second tangent plane is relative with the 4th tangent plane and mutual It is spaced so as to form the second fluting, the extension of first tangent plane, the second tangent plane, the 3rd tangent plane and the 4th tangent plane relative stator tooth Direction inclines or vertical.

14. electric tools as claimed in claim 1, it is characterised in that the electric tool is electric drill.

15. electric tools as described in claim 3,5 or 8, it is characterised in that the circumferential width of the stator tooth is described turn 0.8 to 1.6 times of sub- external diameter.

16. electric tools as described in claim 3,5 or 8, it is characterised in that the radial thickness in the outer yoke portion is outside rotor 0.3 to 0.7 times of footpath.