CN204928523U - Permanent -magnet brushless D.C electric machine - Google Patents

Permanent -magnet brushless D.C electric machine Download PDF

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Publication number
CN204928523U
CN204928523U CN201520586921.0U CN201520586921U CN204928523U CN 204928523 U CN204928523 U CN 204928523U CN 201520586921 U CN201520586921 U CN 201520586921U CN 204928523 U CN204928523 U CN 204928523U
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permanent
electric machine
rotor
magnet
magnet brushless
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章玉胜
陶乔华
张伟
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Positec Power Tools Suzhou Co Ltd
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Positec Power Tools Suzhou Co Ltd
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Abstract

The utility model relates to a permanent -magnet brushless D. C electric machine, include the rotor and encircle the stator of rotor, the rotor includes rotor core, rotor core sets up the permanent magnet groove along circumference, the permanent magnet is installed in the permanent magnet groove, the permanent magnet is in size on the length direction of permanent magnet groove with permanent magnet groove both ends point respectively with correspond between rotor core line of centres's two lines the ratio of the external diameter arc length of rotor is 0.6634-0.72. Above -mentioned permanent -magnet brushless D. C electric machine is through the ratio of the rotor diameter arc length that sets up the permanent magnet width and correspond to make this permanent -magnet brushless D. C electric machine have higher back electromotive force, thereby have higher electromagnetism moment of torsion and electric efficiency under the loading condition.

Description

Permanent-magnet brushless DC electric machine
Technical field
The utility model relates to machine field, particularly relates to a kind of permanent-magnet brushless DC electric machine.
Background technology
Permanent-magnet brushless DC electric machine is the direct current machine being set up magnetic field by one or more permanent magnet, and its performance is similar to the separately excited DC machine of constant excitation megnet electric current, can carry out speed governing easily by change armature voltage.And compared with separated exciting DC motor, there is the advantages such as volume is little, efficiency is high, structure is simple, copper consumption is few, be widely used in various portable electronic equipment or utensil, also be widely used in the industries such as automobile, boats and ships, aviation, machinery, be also widely used in some are as the high, refined, peak products such as camera, video tape recorder.
And at present, due to the restriction of structure, when existing permanent-magnet brushless DC electric machine is used on the electric tool of lasting varying load, the moment of torsion of output is relatively little, and electric efficiency is lower.
Utility model content
Based on this, be necessary that the moment of torsion for permanent-magnet brushless DC electric machine is less, the problem that electric efficiency is lower, provide a kind of output torque comparatively large, the permanent-magnet brushless DC electric machine that electric efficiency is higher.
A kind of permanent-magnet brushless DC electric machine, comprise rotor and the stator around described rotor, described rotor comprises rotor core, described rotor core circumferentially offers permanent magnet trough, described permanent magnet trough is provided with permanent magnet, the size of described permanent magnet on described permanent magnet trough length direction and described permanent magnet trough two-end-point respectively and the ratio of the external diameter arc length of described rotor corresponding between two lines of the described rotor core line of centres be 0.6634 ~ 0.72.
Above-mentioned permanent-magnet brushless DC electric machine, by arranging the ratio of permanent magnet width and corresponding rotor diameter arc length, thus makes this permanent-magnet brushless DC electric machine have higher back electromotive force, thus has higher electromagnetic torque and electric efficiency under that loading condition.
Wherein in an embodiment, form magnetic bridge between described permanent magnet trough two ends and described rotor periphery, described magnetic bridge is of a size of 0.5 ~ 0.8mm at described rotor radial.
Wherein in an embodiment, described magnetic bridge is of a size of 0.5mm at described rotor radial.
Wherein in an embodiment, described permanent magnet quantity is four, adjacent head and the tail interval and the rectangular setting between two of described permanent magnet.
Wherein in an embodiment, described stator is circumferentially with stator slot, and the ratio that the quantity of described stator slot is the number of pole-pairs of rotor described in twice is 3/2.
Wherein in an embodiment, the ratio of the external diameter of described rotor and the external diameter of described stator is 0.5 ~ 0.55.
Wherein in an embodiment, the back electromotive force of the output of described permanent-magnet brushless DC electric machine is trapezoidal wave back electromotive force.
Wherein in an embodiment, when described permanent-magnet brushless DC electric machine is unloaded, the width in the flat-top district of described trapezoidal wave back electromotive force is the electrical degree of 20 ~ 35 °.
Wherein in an embodiment, described stator is circumferentially with Hall element.
Wherein in an embodiment, the angle of the center of the line of described Hall element and described stator center and the notch of described stator slot and the line of described stator center is 10 ~ 20 °.
Accompanying drawing explanation
Fig. 1 is the structural representation of the rotor of the permanent-magnet brushless DC electric machine of an execution mode;
Fig. 2 is the structural representation of the stator of the permanent-magnet brushless DC electric machine of an execution mode;
Fig. 3 is the trapezoidal wave back-emf schematic diagram of an execution mode.
Embodiment
For the ease of understanding the utility model, below with reference to relevant drawings, the utility model is described more fully.Preferred embodiment of the present utility model is given in accompanying drawing.But the utility model can realize in many different forms, is not limited to embodiment described herein.On the contrary, provide the object of these embodiments be make the understanding of disclosure of the present utility model more comprehensively thorough.
It should be noted that, when element is called as " being fixed on " another element, directly can there is element placed in the middle in it on another element or also.When an element is considered to " connection " another element, it can be directly connected to another element or may there is centering elements simultaneously.Term as used herein " vertical ", " level ", "left", "right" and similar statement are just for illustrative purposes.
Unless otherwise defined, all technology used herein and scientific terminology are identical with belonging to the implication that those skilled in the art of the present utility model understand usually.The object of the term used in specification of the present utility model herein just in order to describe specific embodiment, is not intended to be restriction the utility model.Term as used herein " and/or " comprise arbitrary and all combinations of one or more relevant Listed Items.
As shown in Figures 1 and 2, a kind of permanent-magnet brushless DC electric machine (not shown), this permanent-magnet brushless DC electric machine comprises the stator 40 of rotor 20 and surrounding rotor 20, and rotor 20 relative stator 40 is rotated thus produces back electromotive force.
Rotor 20 comprises rotor core 22, and rotor core 22 circumferentially offers permanent magnet trough 222, for installing permanent magnet 24.The width A of permanent magnet 24 on permanent magnet trough 222 length direction and permanent magnet trough 222 two-end-point respectively and the ratio A/B of the external diameter arc length B of rotor 20 corresponding between two lines of rotor core 22 line of centres be 0.6634 ~ 0.72, thus there is higher back electromotive force.Preferably, A/B is 0.6634.
Above-mentioned permanent-magnet brushless DC electric machine, by arranging the ratio of permanent magnet 24 width A and corresponding rotor 20 external diameter arc length B, thus make this permanent-magnet brushless DC electric machine have higher back electromotive force, thus there is higher electromagnetic torque and electric efficiency under that loading condition.
(E represents the back electromotive force that permanent-magnet brushless DC electric machine produces to the electromagnetic torque T=EI/ Ω that permanent-magnet brushless DC electric machine produces, I represents permanent-magnet brushless DC electric machine input phase current, Ω represents rotor velocity), as can be seen here, back-emf E is larger, means that electromagnetic torque is larger, thus under the angular speed of rotor 20 and the identical condition of other loss, there is larger electromagnetic torque T, and then there is higher electric efficiency.
The back electromotive force of the output of permanent-magnet brushless DC electric machine is trapezoidal wave back electromotive force, and the trapezoidal wave of this back electromotive force linearly rises within a certain period of time, enters afterwards and stablizes constant flat-top district, linearly decline after certain hour.And tradition normally used be sinusoidal wave back electromotive force.When same rotating speed two kinds of winding back emf peak values are the same, the no-load speed of sinusoidal wave back-emf brshless DC motor is higher than trapezoidal wave back-emf brshless DC motor, mechanical property is softer than trapezoidal wave back-emf brshless DC motor, and in same current situation, Driving Torque is less than trapezoidal wave back-emf brshless DC motor.Therefore, adopt trapezoidal wave back electromotive force, make permanent-magnet brushless DC electric machine have better performance.
By Electromagnetic Simulation and sample test known, the shape of permanent magnet 24 can affect the output of back electromotive force.That carries out Electromagnetic Simulation using the width A of permanent magnet 24 as variable iterates calculating, test permanent-magnet brushless DC electric machine characteristic curve, the ratio that can obtain as the width A of the permanent magnet 24 and external diameter arc length B of rotor 20 is 0.6634, when permanent-magnet brushless DC electric machine is unloaded, the width in the flat-top district of trapezoidal wave back electromotive force is the electrical degree of 20 ~ 35 °, and moment of torsion and the efficiency of permanent-magnet brushless DC electric machine reach optimum value.Preferably, the width in the flat-top district of trapezoidal wave back electromotive force is the electrical degree of 20 ~ 23 °.Wherein, electrical degree is each point and the line of initial point and the angle of trunnion axis on trapezoidal wave.
Further, in the present embodiment, stator 40 is circumferentially with the stator slot 44 for installing winding, and the ratio of the quantity of stator slot 44 and rotor 20 number of pole-pairs of twice is 3/2, and the ratio of the external diameter of the external diameter of rotor 20 and stator 40 is 0.5 ~ 0.55.
In the present embodiment, permanent magnet 24 quantity is four, and permanent magnet 24 is arranged at adjacent head and the tail interval between two, thus surrounds rectangle.Magnetic bridge 2222 is formed at four top corner regions of rectangle.
Owing to having interval between adjacent permanent magnet 24, therefore the magnetic line of force does not enter rotor core 22, and produces leakage flux at interval.Under the impact of leakage flux, occurred the region higher than peripheral region magnetic density, the magnetic resistance therefore on magnetic circuit increases, thus reduces reluctance torque.
In the present embodiment, permanent magnet trough 222 two ends tilt in a certain angle, and form magnetic bridge 2222 between rotor 20 outer rim, and magnetic bridge 2222 is 0.5 ~ 0.8mm in the size (i.e. the width b of magnetic bridge 2222) of rotor 20 radial direction.Preferably, magnetic bridge 2222 width b is 0.5mm.When the width b of magnetic bridge 2222 is less than 0.5mm, because magnetic bridge 2222 is near rotor 20 outer rim, therefore the mechanical strength of this rotor 20 can be caused not enough, and the centrifugal force that electrode runs up in process can cause rotor 20 deformation and damage, and has higher manufacture process requirement and manufacturing cost.
When magnetic bridge 2222 is saturated, namely electric current be increased to certain value and the magnetic flux of magnetic bridge 2222 no longer increases time, can limit leakage flux, make this permanent-magnet brushless DC electric machine have larger useful flux, the utilance of magnetic material is higher.And when magnetic bridge 2222 width b is greater than 0.8mm, electric current is less, be difficult to reach capacity, electric current then causes motor winding to damage too greatly.So, the width b of magnetic bridge 2222 is limited in 0.5 ~ 0.8mm, magnetic bridge 2222 can be made to be issued to saturated at certain current value, this permanent-magnet brushless DC electric machine is normally worked, and there is good saturation characteristic and maintain the needs of high speed adjustable range.
Stator 40 is circumferentially with Hall element 42 to detect the position of rotor 20 rotating magnetic field, and then by logical AND drive circuit, encourages corresponding winding.When the permanent magnet 24 rotated turns over Hall element 42, Hall element 42 can be made to export low and high level, and then by logical AND drive circuit for winding provides corresponding electric current.In the present embodiment, the angle theta of the center of the line at Hall element 42 center and stator 40 center and the notch of stator slot 44 and the line at stator 40 center is 10 ~ 20 °.
Above-mentioned permanent-magnet brushless DC electric machine, by the setting width A of permanent magnet 24 and the optimum ratio of rotor 20 external diameter arc length, back-emf is made to be trapezoidal wave, and when keeping permanent-magnet brushless DC electric machine unloaded, the width in the flat-top district of trapezoidal wave is the electrical degree of 20 ~ 35 °, makes this permanent-magnet brushless DC electric machine have higher electromagnetic torque and better electric efficiency under that loading condition.And by setting the magnetic bridge 2222 that width is 0.5 ~ 0.8mm, make this permanent-magnet brushless DC electric machine have higher speed adjustable range.Being detected the position of rotor 20 rotating magnetic field by Hall element 42, therefore without the need to installing the devices such as commutator, there is the advantages such as wide range speed control, small size, high efficiency and steady-state speed error are little.
Each technical characteristic of the above embodiment can combine arbitrarily, for making description succinct, the all possible combination of each technical characteristic in above-described embodiment is not all described, but, as long as the combination of these technical characteristics does not exist contradiction, be all considered to be the scope that this specification is recorded.
The above embodiment only have expressed several execution mode of the present utility model, and it describes comparatively concrete and detailed, but therefore can not be interpreted as the restriction to utility model patent scope.It should be pointed out that for the person of ordinary skill of the art, without departing from the concept of the premise utility, can also make some distortion and improvement, these all belong to protection range of the present utility model.Therefore, the protection range of the utility model patent should be as the criterion with claims.

Claims (10)

1. a permanent-magnet brushless DC electric machine, it is characterized in that, comprise rotor and the stator around described rotor, described rotor comprises rotor core, described rotor core circumferentially offers permanent magnet trough, described permanent magnet trough is provided with permanent magnet, the width of described permanent magnet on described permanent magnet trough length direction and described permanent magnet trough two-end-point respectively and the ratio of the external diameter arc length of described rotor corresponding between two lines of the described rotor core line of centres be 0.6634 ~ 0.72.
2. permanent-magnet brushless DC electric machine according to claim 1, is characterized in that, form magnetic bridge between described permanent magnet trough two ends and described rotor periphery, described magnetic bridge is of a size of 0.5 ~ 0.8mm at described rotor radial.
3. permanent-magnet brushless DC electric machine according to claim 2, is characterized in that, described magnetic bridge is of a size of 0.5mm at described rotor radial.
4. permanent-magnet brushless DC electric machine according to claim 1, is characterized in that, described permanent magnet quantity is four, adjacent head and the tail interval and the rectangular setting between two of described permanent magnet.
5. permanent-magnet brushless DC electric machine according to claim 1, is characterized in that, described stator is circumferentially with stator slot, and described in the quantity of described stator slot and twice, the ratio of the number of pole-pairs of rotor is 3/2.
6. permanent-magnet brushless DC electric machine according to claim 1, is characterized in that, the ratio of the external diameter of described rotor and the external diameter of described stator is 0.5 ~ 0.55.
7. permanent-magnet brushless DC electric machine according to claim 1, is characterized in that, the back electromotive force of the output of described permanent-magnet brushless DC electric machine is trapezoidal wave back electromotive force.
8. permanent-magnet brushless DC electric machine according to claim 7, is characterized in that, when described permanent-magnet brushless DC electric machine is unloaded, the width in the flat-top district of described trapezoidal wave back electromotive force is the electrical degree of 20 ~ 35 °.
9. permanent-magnet brushless DC electric machine according to claim 5, is characterized in that, described stator is circumferentially with Hall element.
10. permanent-magnet brushless DC electric machine according to claim 9, is characterized in that, the angle of the center of the line of described Hall element and described stator center and the notch of described stator slot and the line of described stator center is 10 ~ 20 °.
CN201520586921.0U 2015-08-05 2015-08-05 Permanent -magnet brushless D.C electric machine Active CN204928523U (en)

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Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106953443A (en) * 2017-03-28 2017-07-14 安徽美芝制冷设备有限公司 Rotor, motor and compressor for motor
CN107046353A (en) * 2017-02-22 2017-08-15 广东美芝制冷设备有限公司 Motor and the compressor with it
CN108418380A (en) * 2018-04-24 2018-08-17 深圳市精锐昌科技有限公司 A kind of novel brushless motor
CN110236426A (en) * 2018-03-07 2019-09-17 广东美的生活电器制造有限公司 Food processor and base for food processor
CN110236419A (en) * 2018-03-07 2019-09-17 广东美的生活电器制造有限公司 Food processor and its control system and power down display control method
CN110236407A (en) * 2018-03-07 2019-09-17 广东美的生活电器制造有限公司 Food processor and its failure error-reporting method and system
CN110247531A (en) * 2018-03-07 2019-09-17 广东美的生活电器制造有限公司 Food processor and motor for food processor
CN110247484A (en) * 2018-03-07 2019-09-17 广东美的生活电器制造有限公司 Food processor and stator core, motor for food processor
CN110236418A (en) * 2018-03-07 2019-09-17 广东美的生活电器制造有限公司 Food processor and its constant-power control method and control device
EP3818917A1 (en) * 2019-11-06 2021-05-12 Whirlpool Corporation Non-contact magnetic coupler for food processing appliance having small brushless permanent magnet motor
US11936259B2 (en) 2018-03-07 2024-03-19 Guangdong Midea Consumer Electric Manufacturing Co., Ltd. Food processor and electric motor for food processor
US11974698B2 (en) 2018-03-07 2024-05-07 Guangdong Midea Consumer Electric Manufacturing Co., Ltd. Food processor, and power supply board assembly and base for food processor

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN107046353A (en) * 2017-02-22 2017-08-15 广东美芝制冷设备有限公司 Motor and the compressor with it
CN107046353B (en) * 2017-02-22 2023-06-30 广东美芝制冷设备有限公司 Motor and compressor with same
CN106953443A (en) * 2017-03-28 2017-07-14 安徽美芝制冷设备有限公司 Rotor, motor and compressor for motor
CN106953443B (en) * 2017-03-28 2023-11-28 安徽美芝制冷设备有限公司 Rotor for motor, motor and compressor
CN110236419A (en) * 2018-03-07 2019-09-17 广东美的生活电器制造有限公司 Food processor and its control system and power down display control method
CN110236407A (en) * 2018-03-07 2019-09-17 广东美的生活电器制造有限公司 Food processor and its failure error-reporting method and system
CN110247531A (en) * 2018-03-07 2019-09-17 广东美的生活电器制造有限公司 Food processor and motor for food processor
CN110247484A (en) * 2018-03-07 2019-09-17 广东美的生活电器制造有限公司 Food processor and stator core, motor for food processor
CN110236418A (en) * 2018-03-07 2019-09-17 广东美的生活电器制造有限公司 Food processor and its constant-power control method and control device
CN110236426A (en) * 2018-03-07 2019-09-17 广东美的生活电器制造有限公司 Food processor and base for food processor
US11936259B2 (en) 2018-03-07 2024-03-19 Guangdong Midea Consumer Electric Manufacturing Co., Ltd. Food processor and electric motor for food processor
US11974698B2 (en) 2018-03-07 2024-05-07 Guangdong Midea Consumer Electric Manufacturing Co., Ltd. Food processor, and power supply board assembly and base for food processor
CN108418380A (en) * 2018-04-24 2018-08-17 深圳市精锐昌科技有限公司 A kind of novel brushless motor
EP3818917A1 (en) * 2019-11-06 2021-05-12 Whirlpool Corporation Non-contact magnetic coupler for food processing appliance having small brushless permanent magnet motor
US11330938B2 (en) 2019-11-06 2022-05-17 Whirlpool Corporation Non-contact magnetic coupler for food processing appliance having small brushless permanent magnet motor
US12082745B2 (en) 2019-11-06 2024-09-10 Whirlpool Corporation Non-contact magnetic coupler for food processing appliance having small brushless permanent magnet motor

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