CN106300738A - A kind of motor rotor construction - Google Patents

Abstract

The invention provides a motor rotor structure, which includes an iron core and a number of magnets arranged on the iron core; the shape of the magnet is a cylinder, and the thickness of the cross section of the cylinder gradually increases from the middle position to both ends. decrease. The motor rotor structure is mainly used in the motor of the compressor. By designing the magnet structure with unequal thickness, the magnetomotive force generated by the magnet is the largest in the middle position and the smallest at both ends. From the middle position to the two ends, the generated space is gradually reduced. The sinusoidal nature of the back EMF waveform is good, which is beneficial to reduce the total harmonic component, thereby improving the performance of the motor and reducing the noise of the motor; on the other hand, by setting the trimming edge on the magnet, the positioning of the magnet during processing is solved problems, and at the same time reduce the flux leakage at both ends of the magnet.

Description

A motor rotor structure

technical field

The invention relates to the field of motors, in particular to a motor rotor structure.

Background technique

Compressors are widely used in daily electrical appliances, and general compressors are equipped with ferrite variable frequency motors. Referring to FIG. 1 , it shows a schematic cross-sectional view of an existing variable frequency motor. Among them, the thickness of the magnet is the same within the range of the pole arc, and the magnetomotive force generated by the magnet is the same. Therefore, the sinusoidal nature of the back electromotive force waveform is poor, and the harmonic component is large, which affects the performance of the variable frequency motor.

Contents of the invention

The object of the present invention is to provide a motor rotor structure to solve the problems of poor sinusoidality and large harmonic components of the counter electromotive force waveform generated by the magnets in the existing motor rotor.

In order to solve the above technical problems, the present invention provides a motor rotor structure, including an iron core and several magnets arranged on the iron core;

The shape of the magnet is a cylinder, and the thickness of the cross section of the cylinder gradually decreases from the middle position to both ends.

Optionally, the two ends include a first end and a second end, and the relationship between the thickness of the first end, the thickness of the middle position, and the thickness of the second end is as follows:

H2=H3, and

Wherein, H2 and H3 represent the thickness of the first end and the second end respectively, and H1 represents the thickness of the middle position.

Optionally, the iron core is provided with several magnet slots, the several magnet slots are equidistantly distributed around the center of the iron core, and one magnet is arranged in each magnet slot.

Optionally, each magnet slot is provided with a magnetic isolation bridge for reducing magnetic flux leakage of the magnet, and the magnetic isolation bridge is located outside the magnet.

Optionally, both ends of the cross-section of the cylinder include two trimming edges, and the length of each trimming edge ranges from 0.1 mm to 2 mm.

Optionally, the iron core is further provided with a shaft hole, and the shaft hole is located at the center of the iron core.

Optionally, it also includes two end plates for preventing the magnet from falling out, and the two end plates are respectively arranged at two ends of the iron core.

Optionally, the iron core is further provided with rivet holes for fixing the end plate, and the rivet holes are equidistantly distributed around the shaft hole.

Optionally, the number of the magnets is at least two.

Optionally, the magnet is a ferrite magnet.

Optionally, the iron core is composed of several silicon steel sheets stacked and riveted.

The rotor structure of the motor is mainly used in the motor of the compressor. By designing the magnet structure with unequal thickness, the magnetomotive force generated by the magnet is the largest in the middle position and the smallest at both ends. From the middle position to the two ends, the space generated is gradually reduced. The sinusoidal nature of the back EMF waveform is good, which is beneficial to reduce the total harmonic component, thereby improving the performance of the motor and reducing the noise of the motor; on the other hand, by setting the trimming edge on the magnet, the positioning of the magnet during processing is solved problem, and at the same time reduce the flux leakage at both ends of the magnet.

Description of drawings

Fig. 1 is the sectional schematic diagram of existing frequency conversion motor;

Fig. 2 is a schematic cross-sectional view of a variable frequency motor according to an embodiment of the present application;

Fig. 3 is a schematic cross-sectional view of a motor rotor structure according to an embodiment of the present application, wherein a lower magnet is hidden;

Fig. 4 is a partial enlarged view among Fig. 3;

Fig. 5 is the schematic diagram of iron core;

Fig. 6 is a schematic cross-sectional view of a single magnet in an inverter motor according to an embodiment of the application.

Among the figure: 1-stator; 2-rotor; 21-magnet; 22-iron core; 221-magnet groove; 2211-magnetic isolation bridge; 222-rivet hole;

detailed description

The core idea of the present application is to design the magnet 21 in the rotor 2 into a structure of unequal thickness, and the thickness gradually decreases from the middle to both ends, and then the magnetomotive force of the magnet 21 gradually decreases from the middle along the pole arc to the two ends, so that The magnetomotive force is the largest in the middle and gradually decreases toward both ends, so the no-load counter electromotive force generated by the magnet 21 has a good sinusoidal waveform, which is conducive to reducing the total harmonic component. It should be noted that the thickness referred to here refers to the thickness of the cross-section of the magnet.

The motor rotor structure proposed by the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. Advantages and features of the present invention will be apparent from the following description and claims. It should be noted that all the drawings are in a very simplified form and use imprecise scales, and are only used to facilitate and clearly assist the purpose of illustrating the embodiments of the present invention.

Referring to FIG. 2 and FIG. 3 , they are respectively a schematic cross-sectional view of the variable frequency motor and a schematic cross-sectional view of the rotor structure of the motor in this embodiment, wherein FIG. 3 is a part of the rotor of the motor in FIG. 2 .

The variable frequency motor mainly includes a stator 1 and a rotor 2, wherein the stator 1 surrounds the outside of the rotor 2 and is generally fixed on the compressor. The rotor 2 includes several magnets 21 and iron cores 22 .

Referring to Fig. 5, it shows a schematic view of the structure of the iron core 22. The iron core 22 is generally made of silicon steel sheets with a thickness of 0.35mm and then stacked and riveted to form an iron core 22 with a certain thickness. The iron core 22 generally includes Magnet groove 221, rivet hole 222, shaft hole 223 and other structures, in order to reduce the problem of magnetic flux leakage at both ends of magnet 21, triangular magnetic isolation bridges 2211 are respectively designed at both ends of magnet groove 221. The shaft hole 223 is assembled with the crankshaft of the compressor, that is, the rotor 2 is assembled with the compressor through the shaft hole 223 and the crankshaft.

Optionally, the number of magnets 21 is at least two, and preferably the number of magnets 21 is four, six or eight. For convenience of description, four magnets 21 are set in the present embodiment, and the number of corresponding magnet slots 221 is also four. not shown) to prevent the magnet 21 from falling out of the magnet groove 221. A similar balance weight (not shown) is generally placed on one or both ends of the end plate, and the iron core 22, the end plate, and the balance weight are riveted after being penetrated by rivets, so as to ensure that the iron core 22, the end plate, and the balance weight are fixed on the together, and the magnet 21 will not fall out under the blocking of the end plate.

Referring to FIG. 4 and FIG. 6 , it shows a partial enlarged view of FIG. 3 and a schematic cross-sectional view of a single magnet 21 . The structure of the magnet 21 will be described in detail below in conjunction with these two drawings.

The magnet 21 is designed to have a structure of unequal thickness. The shape of the magnet 21 is a cylinder. The thickness of the cross section of the cylinder gradually decreases from the middle position to the two ends, and the magnetomotive force of the magnet 21 decreases gradually from the center along the pole arc to the two ends. Small, so that the magnetomotive force is the largest in the middle, gradually decreases to both sides, and the two ends are the smallest.

Preferably, the cross-section of the magnet 21 is approximately crescent-shaped, thin at both ends, thick at the middle, and symmetrical along the middle. For convenience of description, the cross section of the column includes a first end, a second end and a middle position. Figure 5 shows the thicknesses of the first end, the second end and the middle position respectively. When the ratio of the thickness of the two ends of the magnet 21 to the thickness of the middle position is 0.125-0.450, the harmonic component of the counter electromotive force is the smallest and the sinusoidality is the best, that is :

When H2=H3 and When , the harmonic component of the back EMF waveform is the smallest.

Wherein, H2 and H3 represent the thickness of the first end and the second end respectively, and H1 represents the thickness of the middle position.

Preferably, the magnet 21 is a ferrite magnet.

In order to facilitate the processing of the magnet 21 , two trimming edges are respectively designed at both ends of the magnet 21 for convenient positioning when the magnet 21 is processed. The lengths of the two cut sides are marked in Fig. 4, which are represented by L1 and L2 respectively, and L1 = 0.1 mm to 2 mm, and L2 = 0.1 mm to 2 mm.

The motor rotor structure provided by the present application has the following beneficial effects: the motor rotor structure is mainly used in the motor of the compressor. By designing a magnet structure with unequal thickness, the magnetomotive force generated by the magnet 21 is the largest in the middle and the two ends are the smallest. If the middle position gradually decreases toward both ends, the generated no-load back electromotive force waveform is good in sinusoidality, which is beneficial to reduce the total harmonic component, thereby improving the performance of the motor and reducing the noise of the motor; on the other hand, through the magnet The setting of trimming solves the positioning problem of the magnet during processing, and at the same time reduces the magnetic flux leakage at both ends of the magnet.

The above description is only a description of the preferred embodiments of the present invention, and does not limit the scope of the present invention. Any changes and modifications made by those of ordinary skill in the field of the present invention based on the above disclosures shall fall within the protection scope of the claims.

Claims (11)

1. a motor rotor construction, it is characterised in that include iron core and the some Magnet being arranged on described iron core；

Described Magnet be shaped as cylinder, the thickness of the cross section of described cylinder is gradually reduced to two ends by centre position.

2. motor rotor construction as claimed in claim 1, it is characterised in that described two ends include the first end and the second end, institute The relation of the thickness stating the thickness of the first end, the thickness in described centre position and described second end is as follows:

H2=H3, and

Wherein, H2 and H3 represents thickness and the thickness of described second end of described first end respectively, and H1 represents the thickness in centre position Degree.

3. motor rotor construction as claimed in claim 1, it is characterised in that be provided with several Magnet grooves on described iron core, Several Magnet grooves described are equidistantly distributed around the center of described iron core, arrange a Magnet in each Magnet groove.

4. motor rotor construction as claimed in claim 3, it is characterised in that be provided with for reducing magnetic on each Magnet groove Ferrum leakage field every magnetic magnetic bridge, the described outside being positioned at described Magnet every magnetic magnetic bridge.

5. motor rotor construction as claimed in claim 1, it is characterised in that the two ends of the cross section of described cylinder all include two Individual trimming, the length range of each trimming is 0.1mm～2mm.

6. motor rotor construction as claimed in claim 1, it is characterised in that be additionally provided with axis hole, described axle on described iron core Hole is positioned at the center of described iron core.

7. motor rotor construction as claimed in claim 6, it is characterised in that also include for prevent described Magnet from dropping out two Individual end plate, said two end plate is respectively arranged at the two ends of described iron core.

8. motor rotor construction as claimed in claim 7, it is characterised in that be additionally provided with on described iron core for fixing described The rivet hole of end plate, described rivet hole is equidistantly distributed around described axis hole.

9. motor rotor construction as claimed in claim 1, it is characterised in that the quantity of described Magnet is at least two.

10. motor rotor construction as claimed in claim 1, it is characterised in that described Magnet is ferrite magnet.

11. motor rotor constructions as claimed in claim 1, it is characterised in that described iron core is got up by some silicon steel sheet stack rivetings Composition.