CN204103630U - For the permanent magnet of motor - Google Patents

Abstract

A kind of permanent magnet for motor, described motor includes rotor and motor stator, form air gap between described rotor and motor stator, it is characterized in that: described permanent magnet includes basal surface, the outer surface of this basal surface and described rotor fits; Upper end face, on this, end face is relative with described air gap and establish, the outline line of described upper end face is curve that is sinusoidal wave and triple-frequency harmonics function superposition, the utility model has the advantage of: add optimum triple-frequency harmonics function by a sine and obtain new magnet structure, under the prerequisite of torque pulsation not increasing motor, add torque to export, motor has the advantages such as power density is high, Gao imitates Jie Neng ﹑ smooth movement, noise is low.

Description

For the permanent magnet of motor

Technical field

The utility model relates to a kind of permanent magnet, particularly a kind of permanent magnet for the mounted magneto in face.

Background technology

The rotor of existing mounted magneto adopts the permanent magnet do not had through cutting pole process usually, as shown in Figure 1, the outer cross section of permanent magnet of this motor is cylindrical, the Gas-gap Magnetic Field Resonance Wave content produced by this permanent magnet is high, thus cause the pulsation that is large and operation torque of the cogging torque of motor large, produce larger vibration & noise, affect control precision and the positioning precision of whole set equipment.

In order to reduce the cogging torque of motor and run torque pulsation, the control precision of raising equipment, in the prior art, existing application number is that the Chinese invention patent " permanent magnet motor and the permanent magnet for motor " of 201080013643.X discloses and a kind ofly has the motor of permanent magnet rotor and a kind of permanent magnet, in described motor, permanent magnet is assembled on the outer surface of cylindrical rotor, the permanent magnet forming rotor magnetic pole is shaped as and makes the air gap of motor be constant substantially at the middle part of magnetic pole, and described air gap increases in straight line mode forward substantially when moving towards pole edge, permanent magnet has uniform thickness at middle part, and attenuate towards edge.

The motor of above-mentioned patent is by changing the shape of conventional permanent magnet, its permanent magnet is shaped as and makes the air gap of motor be constant substantially at the zone line of magnetic pole, when moving from the zone line of magnetic pole to the edge of magnetic pole, described air gap increases in straight line mode forward substantially, and the width of described zone line in rotor tangential direction is at least half of magnet width.The permanent magnet shape of this patent reduces moment ripple and the profile of tooth moment of motor, but well cannot control the average torque of motor, it is the same that this and the method adopting SIN function to process at present realize permanent magnet, as shown in Figure 2, although the method can reduce the cogging torque of motor and run torque pulsation, but also reduce the average torque of motor simultaneously, and then reduce torque density, the operational efficiency of motor.Therefore, how under the cogging torque reducing motor and the prerequisite running torque pulsation, ensure that the average torque of motor and operational efficiency are the mounted magneto in face problems urgently to be resolved hurrily, need to make further improvement.

Utility model content

Technical problem to be solved in the utility model is the permanent magnet of the mounted magneto in little face that provides a kind of delivery efficiency of motor high for above-mentioned prior art present situation and Driving Torque is pulsed.

The utility model solves the problems of the technologies described above adopted technical scheme: a kind of permanent magnet for motor, described motor includes rotor and motor stator, form air gap between described rotor and motor stator, it is characterized in that: described permanent magnet includes

Basal surface, the outer surface of this basal surface and described rotor fits;

Upper end face, on this, end face is relative with described air gap and establish, and the outline line of described upper end face is curve that is sinusoidal wave and triple-frequency harmonics function superposition, and the function that the concrete shape of this curve is represented by following formula (I) is determined:

$\left\{\begin{array}{c}{\mathrm{\Δh}}_m\left(\mathrm{\θ}\right)={\mathrm{\Δm}}_a[\sin \left(\mathrm{p\θ}\right)+a\sin \left(3\mathrm{p\θ}\right)]\\ {\mathrm{\Δm}}_a=\frac{1}{8a}{\left(\frac{1+3a}{12a}\right)}^{-\frac{3}{2}}\end{array}\right.---\left(I\right)$

Wherein, above-mentioned formula (I) adopts polar coordinate system, the Δ h in formula (I) _m(θ) be the footpath, pole of any point M on the upper top surface profile line of described permanent magnet, θ be described permanent magnet upper top surface profile line on the polar angle of any point M; P is motor number of pole-pairs; A is the amplitude of triple-frequency harmonics function; Δ m _ait is the value changed with the amplitude a of triple-frequency harmonics function.

Compared with prior art, the utility model has the advantage of: add optimum triple-frequency harmonics function by a sine and obtain new magnet structure, the magnetic field harmonics produced due to this permanent magnet 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 make to adopt the mounted magneto in the face of this permanent magnet shape to have power density be high, the advantage such as Gao imitates Jie Neng ﹑ smooth movement, noise is low.

Accompanying drawing explanation

Fig. 1 is one of conventional permanent magnet structural representation of the prior art (rectangle).

Fig. 2 is conventional permanent magnet structural representation two (sine wave) of the prior art.

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

Fig. 4 is the motor rotor construction schematic diagram shown in Fig. 3.

Fig. 5 is the magnet structure schematic diagram of the utility model embodiment rotor.

Fig. 6 is the schematic diagram that the permanent magnet external surface shape of the utility model embodiment changes with polar angle.

Fig. 7 is the schematic diagram that the permanent magnet torque of the utility model embodiment changes with triple-frequency harmonics amplitude.

Fig. 8 is the magnet structure schematic diagram that the syllogic processing method of the utility model embodiment realizes.

Fig. 9 is the comparison diagram that the motor of the present embodiment permanent magnet and the cogging torque of existing motor change with rotor-position.

Figure 10 is the comparison diagram that the motor of the present embodiment permanent magnet and the torque of existing 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. 7, the present embodiment relates to the method for designing of a kind of permanent magnet and this permanent magnet, the permanent magnet of the present embodiment is used for surface stuck type motor, be illustrated in figure 3 the general assembly drawing of this motor, motor is made up of motor stator 1 and rotor 2, and permanent magnet 3 is fixed on the surface of rotor 2 by High-strength glue.

The distribution of air-gap field during machine operation and the shape of permanent magnet closely related, traditional permanent magnet 3 ' is generally rectangular configuration as shown in Figure 1, the magnetic field harmonics content of the square-wave profile produced during the work of this permanent magnet 3 ' is high, thus causes the pulsation of the cogging torque of motor and operation torque large; Permanent magnet 3 shown in Fig. 2 " have employed the sinusoidal wave magnetic field distributed, although its amplitude size is identical with square wave field, fundamental voltage amplitude reduces, thus reduces the torque density of motor, reduces overall efficiency.

Sine wave and triple-frequency harmonics superpose by the permanent magnet 3 of the present embodiment, obtain the magnet structure with novel curved surface profile shape.The permanent magnet 3 of the present embodiment includes basal surface and upper end face, and wherein, basal surface is circular arc, and the outer surface of this basal surface and rotor fits;

Upper end face arcuately, the air gap formed between rotor and motor stator, on this, end face is relative with air gap and establish, the outline line of upper end face is curve that is sinusoidal wave and triple-frequency harmonics function superposition, the function that the concrete shape of this curve is represented by following formula (I) is determined, see Fig. 5, Fig. 6:

$\left\{\begin{array}{c}{\mathrm{\Δh}}_m\left(\mathrm{\θ}\right)={\mathrm{\Δm}}_a[\sin \left(\mathrm{p\θ}\right)+a\sin \left(3\mathrm{p\θ}\right)]\\ {\mathrm{\Δm}}_a=\frac{1}{8a}{\left(\frac{1+3a}{12a}\right)}^{-\frac{3}{2}}\end{array}\right.---\left(I\right)$

Above-mentioned formula (I) adopts polar coordinate system, the Δ h in formula (I) _m(θ) be the footpath, pole of any point M on the upper top surface profile line of described permanent magnet 3, θ be described permanent magnet 3 upper top surface profile line on the polar angle of any point M; P is motor number of pole-pairs; A is the amplitude of triple-frequency harmonics function; Δ m _ait is the value changed with the amplitude a of triple-frequency harmonics function.

Wherein, the amplitude a of triple-frequency harmonics function is the numerical value of a change, and as a=0, the upper top surface profile line of permanent magnet 3 is the curve shown in Fig. 6 dotted line t1, and now, permanent magnet 3 shape can by formula Δ h with the change of position pole coordinate parameter _m(θ)=Δ msin (p θ) represents, Δ m is the maximum ga(u)ge (i.e. the height of curve peak) of permanent magnet 3; As a=1/6, triple-frequency harmonics function is the curve shown in Fig. 6 dotted line t2, and now, permanent magnet 3 shape can by formula with the change of position pole coordinate parameter represent, can find out that the torque of motor exports maximum, see Fig. 7 when injection triple-frequency harmonics amplitude a is the first-harmonic of 1/6.Dotted line t1 and dotted line t2 represents the curve of SIN function and triple-frequency harmonics function respectively, and namely permanent magnet 3 true form of the present embodiment is obtained by these two curve combinings; Visible, the peak of the curve t1 that SIN function obtains is 1.15 times of the peak being added the curve T that triple-frequency harmonics function obtains by SIN function.

But the permanent magnet 3 obtained shown in Fig. 6 needs to add optimum triple-frequency harmonics function by a sine 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 a kind of Design of Permanent Magnet method that can substitute the above-mentioned permanent magnet simplification course of processing, and see Fig. 8, this method for designing includes following steps:

(1), setting permanent magnet basal surface shape be the arc surface of fitting with the outer surface of rotor, the radius size of this arc surface is determined by the radius size of rotor;

(2), when setting the amplitude a=1/6 of triple-frequency harmonics function, now the upper end face curve shape of permanent magnet is by the function representation of following formula (II):

${\mathrm{\Δh}}_m\left(\mathrm{\θ}\right)=\frac{2\sqrt{3}}{3}[\sin \left(\mathrm{p\θ}\right)+\frac{1}{6}\sin \left(3\mathrm{p\θ}\right)]---\left(\mathrm{II}\right)$

(3), by the curve that the function in formula (II) is formed substituted by the camber line that three sections connect successively, 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;

(4) the curve peak Δ h that the function in formula (II) is formed, is set _m(θ) _maxthe point tangent with the horizontal line representing motor gas-gap is P1, the curve minimum point Δ h that the function in setting formula (II) is formed _m(θ) _minfor P2;

(5), described top arc by with the maximum radius of described permanent magnet for radius and respectively through described some P1, some P2 drawn by circular arc determine;

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

(7), left half arc, top arc be connected successively with right half arc, the camber line formed is the upper top surface profile curve of permanent magnet, and, left half arc, top arc and right half arc between be the connection that smoothly transits.

Can see, its contour curve of the permanent magnet that above-mentioned method for designing obtains is formed by three sections of circular sliding slopes, and the permanent magnet 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 permanent magnet maximum radius, the curve of both sides is also determined by the mode of step (4) and step (6) by left half arc and right half arc respectively, this just enormously simplify the course of processing, reduce difficulty of processing.

Figure 9 shows that the cogging torque comparison diagram of the mounted magneto in face of different permanent magnet shape, Figure 10 shows that the electromagnetic torque comparison diagram of the mounted magneto in face in nominal load situation of different permanent magnet shape; As can be seen from the figure, relative to the mounted magneto in traditional face, can torque ripple reduction by the permanent magnet adding the design of triple-frequency harmonics functional based method with sine, compare the magneto that sine 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 permanent magnet not only can reduce permanent magnet, and its average torque delivery efficiency with cut pole and triple-frequency harmonics with the sine of standard and cut pole and superpose compared with the permanent magnet that designs and obtain and also increase, and torque pulsation does not increase, therefore using the middle sine of syllogic designed arc-shaped appearance method place of equation (II) to cut pole and triple-frequency harmonics, 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. for a permanent magnet for motor, described motor includes rotor and motor stator, forms air gap, it is characterized in that between described rotor and motor stator: described permanent magnet includes

Basal surface, the outer surface of this basal surface and described rotor fits;

Upper end face, on this, end face is relative with described air gap and establish, and the outline line of described upper end face is curve that is sinusoidal wave and triple-frequency harmonics function superposition, and the function that the concrete shape of this curve is represented by following formula is determined:

$\left\{\begin{array}{c}{\mathrm{\Δh}}_m\left(\mathrm{\θ}\right)={\mathrm{\Δm}}_a[\sin \left(\mathrm{p\θ}\right)+a\sin \left(3\mathrm{p\θ}\right)]\\ {\mathrm{\Δm}}_a=\frac{1}{8a}{\left(\frac{1+3a}{12a}\right)}^{-\frac{3}{2}}\end{array}\right.---\left(I\right)$

Wherein, above-mentioned formula (I) adopts polar coordinate system, the Δ h in formula (I) _m(θ) be the footpath, pole of any point M on the upper top surface profile line of described permanent magnet, θ be described permanent magnet upper top surface profile line on the polar angle of any point M; P is motor number of pole-pairs; A is the amplitude of triple-frequency harmonics function; Δ m _ait is the value changed with the amplitude a of triple-frequency harmonics function.