Permanent magnet dc motor and food processor

Abstract

The invention provides a permanent magnet DC motor for a food processor, comprising a stator; A rotor comprising a commutator, the commutator being provided with at least four commutating tabs; A first electrode carbon brush in contact with the commutator; A second electrode carbon brush in contact with the commutator; And two elastic members respectively connected with the first electrode carbonbrush and the second electrode carbon brush so that the first electrode carbon brush and the second electrode carbon brush contact with the commutator under the pressure of the elastic member; Whereinthe resistivity of the first electrode carbon brush is greater than the resistivity of the second electrode carbon brush when the level of the generated commutation spark between the first electrodecarbon brush and the commutator is greater than the level of the generated commutation spark between the second electrode carbon brush and the commutator. By arranging a carbon brush with relatively high resistivity on the side with large commutation spark, the discharge current of the carbon brush on the side is reduced, and the commutation spark at the carbon brush is reduced, so that the wear rates of the carbon brushes on both poles are the same, and the service life of the permanent magnet DC motor is effectively prolonged.

Description

technical field [0001] The invention belongs to the technical field of kitchen utensils, and in particular relates to a permanent magnet DC motor and a food processor. Background technique [0002] At present, when the output torque of the permanent magnet DC motor in the existing food processor is greater than or equal to 0.5N.m, the speed is less than 10000rpm, and when the speed is greater than 10000rpm, the commutation of the motor will deteriorate and produce more than 2 levels of commutation Sparks, especially the commutation sparks of motors with a rated voltage of 220V and above, because the positive and negative carbon brushes in the prior art use the same material, and the positive and negative voltage drops of permanent magnet DC motors are quite different, so The commutation sparks of the positive and negative poles and the wear rate of the carbon brushes are also very different, which will cause the carbon brushes of one pole to wear more severely than the carbo...

AI Technical Summary

Problems solved by technology

[0002] At present, when the output torque of the permanent magnet DC motor in the existing food processor is greater than or equal to 0.5N.m, the speed is less than 10000rpm, and when the speed is greater than 10000rpm, the commutation of the motor will deteriorate and produce more than 2 levels of commutation Sparks, especially the commutation sparks of motors with a rated voltage of 220V and above, because the positive and negative carbon brushes in the prior art use the same material, and the positive and negative voltage drops of permanent magnet DC motors are quite different, so The commutation sparks of the positive and negative poles and the wear rate of the carbon brushes are also very different, which will cause the carbon brushes of one pole to wear more severely than the carbon brushes of the other pole, thus greatly reducing the service life of the motor

[0003] The existing solution is to lengthen the carbon brush on the original basis to meet the service life of the motor. However, it not only increases the production cost of the motor, but also does not solve the problem that the commutation spark accelerates the electrical wear of one pole of the carbon brush.

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