CN204103629U - The rotor core of built-in permanent magnetic motor - Google Patents

Abstract

A kind of rotor core of built-in permanent magnetic motor, described rotor core is circumferentially uniform is embedded with multiple permanent magnet, it is characterized in that: the outer rim of the described rotor core of each permanent magnet corresponding includes basal surface, and the surface of this basal surface and built-in permanent magnetic body fits; Upper end face, on this, end face is relative with the stator core of described motor and establish and form air gap, the outline line of the upper end face intersection of described air gap and described rotor core is the curve of anticosine ripple and triple-frequency harmonics function superposition, the utility model has the advantage of: add by an inverse cosine function outer rim shape that optimum triple-frequency harmonics function obtains new rotor core, under the prerequisite of torque pulsation not increasing motor, add torque to export, motor is had advantages such as power density is high, Gao imitates Jie Neng ﹑ smooth movement, noise is low.

Description

The rotor core of built-in permanent magnetic motor

Technical field

The utility model relates to a kind of rotor core, particularly a kind of rotor core for built-in permanent magnetic motor.

Background technology

The permanent magnet of built-in permanent magnetic motor directly embeds in the rotor of motor, a kind of rotor of built-in permanent magnetic motor the Chinese utility model patent " a kind of rotor of built-in permanent magnetic motor " being ZL201320336256.0 as the existing patent No. in prior art discloses, it comprises the rotor core of sheet laminated structure, embeds the permanent magnet in rotor core; Space is had, by encapsulating fixed permanent magnet in space between permanent magnet and rotor core.Rotor core due to sheet laminated structure can hinder the flowing of casting glue, therefore in described space, inserts encapsulating pipe, with auxiliary encapsulating; The surfaces externally and internally of encapsulating pipe is all very smooth, and sidewall is provided with six through holes, is arranged on both sides along encapsulating pipe length direction.

Rotor core in above-mentioned patent through cutting pole process, the Gas-gap Magnetic Field Resonance Wave content produced between rotor core and motor stator is high, thus cause the cogging torque of motor, run torque pulsation large.In order to reduce the cogging torque of motor and run torque pulsation, built-in permanent magnetic motor as shown in Figure 2, the permanent magnet 3 of this motor " be embedded at rotor core 2 " in, can to rotor core 2 " and electronics stator 1 " between air gap 4 " length carries out anticosine and cuts pole process; although the method can reduce the cogging torque of motor and run torque pulsation; also reduce the average torque of motor, thus reduce torque density, the operational efficiency of motor simultaneously.Therefore, need to make further improvement.

Utility model content

Technical problem to be solved in the utility model provides a kind of delivery efficiency of motor high for above-mentioned prior art present situation and the rotor core of Driving Torque is pulsed little built-in permanent magnetic motor.

The utility model solves the problems of the technologies described above adopted technical scheme: a kind of rotor core of built-in permanent magnetic motor, described rotor core is circumferentially uniform is embedded with multiple permanent magnet, it is characterized in that: the outer rim of the described rotor core of each permanent magnet corresponding includes

Basal surface, the surface of this basal surface and built-in permanent magnetic body fits;

Upper end face, on this, end face is relative with the stator core of described motor and establish and form air gap, the outline line of the upper end face intersection of described air gap and described rotor core is the curve of anticosine ripple and triple-frequency harmonics function superposition, and the function that the concrete shape of this curve is represented by following formula (I) is determined:

$L_g\left(\mathrm{\θ}\right)=\frac{\sqrt{3}{L}_{\mathrm{gd}}}{2(\cos \left(\frac{\mathrm{\π}}{{\mathrm{\τ}}_p}\mathrm{\θ}\right)-a\cos \left(3\frac{\mathrm{\π}}{{\mathrm{\τ}}_p}\mathrm{\θ}\right))}---\left(I\right)$

Above-mentioned formula (I) adopts polar coordinate system, wherein, and the L in above-mentioned formula (I) _gthe footpath, pole of any point M on the outline line of q upper end face intersection that () is described air gap and rotor core, q be the upper end face intersection of described air gap and rotor core outline line on the polar angle of any point M; t _pfor pole span; A is the amplitude injecting triple-frequency harmonics; L _gfor minimal air gap distance; L _gdfor pole span.

As preferred further, as a=1/6, the curvilinear function of described formula (I) is as follows:

$L_g\left(\mathrm{\θ}\right)=\frac{\sqrt{3}{L}_{\mathrm{gd}}}{2(\cos \left(\frac{\mathrm{\π}}{{\mathrm{\τ}}_p}\mathrm{\θ}\right)-\frac{1}{6}\cos \left(3\frac{\mathrm{\π}}{{\mathrm{\τ}}_p}\mathrm{\θ}\right))}---\left(\mathrm{II}\right)$

Now, the torque of motor exports maximum.

Compared with prior art, the utility model has the advantage of: add by an inverse cosine function outer rim shape that optimum triple-frequency harmonics function obtains new rotor core, because the Gas-gap Magnetic Field Resonance Wave produced between rotor core and stator core only adds triple-frequency harmonics, but its tertiary current of Y-connection winding is not existed, thus under the prerequisite of torque pulsation not increasing motor, add torque to export, and the built-in permanent magnetic motor adopting this rotor core shape is had advantages such as power density is high, Gao imitates Jie Neng ﹑ smooth movement, noise is low.

Accompanying drawing explanation

Fig. 1 is one of conventional rotors core structure schematic diagram of the prior art.

Fig. 2 is conventional rotors core structure schematic diagram two of the prior art.

Fig. 3 is the motor general assembly drawing of the utility model embodiment.

Fig. 4 is the rotor core structure schematic diagram shown in Fig. 3.

Fig. 5 is the schematic diagram that the motor gas-gap length of the utility model embodiment changes with rotor-position.

The rotor core contour structure schematic diagram of the syllogic processing method realization of Fig. 6 the utility model embodiment.

Fig. 7 is the comparison diagram that the motor of the present embodiment and the cogging torque of prior art motor change with rotor-position.

Fig. 8 is the comparison diagram that the motor of the present embodiment and the torque of prior art motor change with rotor-position.

Embodiment

Under by reference to the accompanying drawings embodiment the utility model is described in further detail.

As shown in Fig. 3 ~ Fig. 8, the present embodiment relates to a kind of rotor core of built-in permanent magnetic motor, is illustrated in figure 3 the general assembly drawing of this motor, and motor is made up of motor stator 1 and rotor core 2, and permanent magnet 3 is embedded on the rotor along the circumference of rotor core 2.

The distribution of air-gap field during machine operation and the performance of motor have closely related, the gas length of tradition embedded actuator with rotor-position change as shown in Figure 1, the permanent magnet 3 ' of embedded actuator is embedded on rotor core 2 ', air gap 4 ' is formed between motor stator 1 ' and rotor core 2 ', the magnetic field harmonics content of the square-wave profile produced during this machine operation is high, thus causes the pulsation of the cogging torque of motor and operation torque large; Air gap 4 shown in Fig. 2 " length have employed anticosine wavelength-division cloth, although its amplitude size is identical with square wave field, fundamental voltage amplitude reduces, thus reduces the torque density of motor, reduces overall efficiency.

The present embodiment, to the superposition having air gap 4 length formed between motor stator 1 and rotor core 2 to have employed anticosine ripple and triple-frequency harmonics, obtains the rotor core outer rim with novel curved surface profile shape.

The outer rim of the rotor core 2 of the present embodiment each permanent magnet 3 corresponding includes basal surface and upper end face; Wherein, the surface of basal surface and built-in permanent magnetic body 3 fits; Upper end face is relative with the iron core of motor stator 1 and establish and form air gap 4, on this, the outline line of end face and air gap 4 intersection is the curve of anticosine ripple and triple-frequency harmonics function superposition, and the function that the concrete shape of this curve is represented by following formula (I) is determined:

$L_g\left(\mathrm{\θ}\right)=\frac{\sqrt{3}{L}_{\mathrm{gd}}}{2(\cos \left(\frac{\mathrm{\π}}{{\mathrm{\τ}}_p}\mathrm{\θ}\right)-a\cos \left(3\frac{\mathrm{\π}}{{\mathrm{\τ}}_p}\mathrm{\θ}\right))}---\left(I\right)$

Above-mentioned formula (I) adopts polar coordinate system, wherein, and the L in above-mentioned formula (1) _gq () is described air gap 4 and the footpath, pole of any point M on the outline line of the upper end face intersection of rotor core 2 iron core, q is described air gap 4 and the polar angle of any point M on the outline line of the upper end face intersection of rotor core 2 iron core; t _pfor pole span; A is the amplitude injecting triple-frequency harmonics; L _gfor minimal air gap distance; L _gdfor pole span.

When setting a=1/6, now the Driving Torque of motor is maximum, and obtain the function of following formula, curve shape is see Fig. 5:

$L_g\left(\mathrm{\θ}\right)=\frac{\sqrt{3}{L}_{\mathrm{gd}}}{2(\cos \left(\frac{\mathrm{\π}}{{\mathrm{\τ}}_p}\mathrm{\θ}\right)-\frac{1}{6}\cos \left(3\frac{\mathrm{\π}}{{\mathrm{\τ}}_p}\mathrm{\θ}\right))}---\left(\mathrm{II}\right)$

It is the outline line of the upper end face intersection of air gap 4 and rotor core 2 iron core due to above-mentioned curve, namely the curve of gas length and the outer contour of rotor core are identical, namely can process the shape of the electronics rotor core of the magnetic field requirements meeting built-in permanent magnetic motor according to above-mentioned curve.

But the rotor core 2 obtained shown in Fig. 5 needs to add optimum triple-frequency harmonics function by an anticosine during fabrication and realizes, and its course of processing is complicated, and manufacturing cost is high.In order to simplify manufacture process, the present embodiment also proposed and a kind ofly can simplify and substitute the rotor core method for designing of the processing method of above-mentioned rotor core, and see Fig. 6, this method for designing includes following steps:

(1), set the amplitude a=1/6 of described triple-frequency harmonics function, the upper end face curve shape of described rotor core is by the function representation of following formula (II):

$L_g\left(\mathrm{\θ}\right)=\frac{\sqrt{3}{L}_{\mathrm{gd}}}{2(\cos \left(\frac{\mathrm{\π}}{{\mathrm{\τ}}_p}\mathrm{\θ}\right)-\frac{1}{6}\cos \left(3\frac{\mathrm{\π}}{{\mathrm{\τ}}_p}\mathrm{\θ}\right))}---\left(\mathrm{II}\right)$

(2), by the curve that the function in described formula (II) is formed substituted by the camber line that three sections connect successively, described three sections of camber lines are respectively left half arc, top arc and right half arc, and wherein left half arc and right half arc are for being symmetrical arranged;

(3) the curve peak L that the function in described formula (II) is formed, is set _g(q) _maxthe point tangent with the horizontal line representing motor gas-gap is P1, sets the curve minimum point L that the function in described formula (II) is formed _g(q) _minfor P2;

(4), described top arc by with the maximum radius of described rotor core for radius and respectively through described some P1, some P2 drawn by circular arc determine;

(5), described left half arc by respectively through described some P1, P2 and the circular arc tangent with the horizontal line of described motor gas-gap determine, described right half arc is symmetrical arranged with described left half arc and arc radius is equal;

(6), described left half arc, top arc be connected successively with right half arc, the camber line formed is the upper top surface profile curve of described rotor core.

Can see, its contour curve of the rotor core that above-mentioned method for designing obtains is formed by three sections of circular sliding slopes, and the rotor core actual curve shape obtained by formula (II) is in the middle recessed a little and structure of two ends projection, the amplitude recessed due to centre is very little, in the actual course of processing, middle lower concave part can be similar to by the circularity substitution being radius with rotor core maximum radius, the curve of both sides is also determined by the mode of step (3) and step (5) by left half arc and right half arc respectively, this just enormously simplify the course of processing, reduce difficulty of processing.

Figure 7 shows that the cogging torque comparison diagram of the embedded actuator of different rotor core outer rim shapes, Figure 8 shows that the electromagnetic torque comparison diagram of the embedded actuator of different rotor core shapes in nominal load situation; As can be seen from the figure, relative to traditional built-in permanent magnetic motor, can torque ripple reduction by the rotor core outer rim adding the design of triple-frequency harmonics functional based method by anticosine, compare the magneto that anticosine cuts pole, its average torque exports and improves 11.5%, and torque pulsation does not increase.

On the other hand, the syllogic designed arc-shaped appearance method that the present embodiment adopts obtains the difficulty of processing that rotor core not only can reduce rotor core, and its average torque delivery efficiency with cut pole and triple-frequency harmonics by the anticosine of standard and cut pole and superpose compared with the rotor core that designs and obtain and also increase, and torque pulsation does not increase, therefore using and cut pole and triple-frequency harmonics by anticosine in syllogic designed arc-shaped appearance method place of equation (II) to cut the permanent magnet that method for designing that pole superposes processes the present embodiment be feasible, is also a kind of more practical and efficient method.

Claims (1)

1. a rotor core for built-in permanent magnetic motor, described rotor core is circumferentially uniform is embedded with multiple permanent magnet, it is characterized in that: the outer rim of the described rotor core of each permanent magnet corresponding includes

Basal surface, the surface of this basal surface and built-in permanent magnetic body fits;

Upper end face, on this, end face is relative with the stator core of described motor and establish and form air gap, the outline line of the upper end face intersection of described air gap and described rotor core is the curve of anticosine ripple and triple-frequency harmonics function superposition, and the function that the concrete shape of this curve is represented by following formula (I) is determined:

Above-mentioned formula (I) adopts polar coordinate system, wherein, and the L in above-mentioned formula (I) _g(θ) be the footpath, pole of any point M on the outline line of the upper end face intersection of described air gap and rotor core, θ be the upper end face intersection of described air gap and rotor core outline line on the polar angle of any point M; τ _pfor pole span; A is the amplitude injecting triple-frequency harmonics; L _gfor minimal air gap distance; L _gdfor pole span.