CN109327169B

CN109327169B - Household appliance capable of providing cold air, driving circuit and permanent magnet direct current motor thereof

Info

Publication number: CN109327169B
Application number: CN201710534213.6A
Authority: CN
Inventors: 覃海岩; 罗志强
Original assignee: Johnson Electric Shenzhen Co Ltd
Current assignee: Johnson Electric Shenzhen Co Ltd
Priority date: 2017-07-03
Filing date: 2017-07-03
Publication date: 2022-04-26
Anticipated expiration: 2037-07-03
Also published as: CN109327169A; JP2019017240A; KR20190004234A

Abstract

The invention provides a household appliance driving circuit capable of providing cold air, which comprises a permanent magnet direct current motor, a rectifier and a voltage dividing resistor. One end of the divider resistor is connected with a first input end of the rectifier, the other end of the divider resistor is used for being connected with a first end of an alternating current power supply, a second input end of the rectifier is used for being connected with a second end of the alternating current power supply, an output end of the rectifier is connected with the permanent magnet direct current motor, the permanent magnet direct current motor comprises a plurality of capacitors, each capacitor comprises a first electrode and a second electrode, the first electrodes of the capacitors are electrically connected together, and the second electrodes of the capacitors are electrically connected to a commutator bar respectively. The driving voltage of the permanent magnet direct current motor is 50V to 100V. The household appliance driving circuit reduces the voltage at two ends of the divider resistor and reduces the heating of the divider resistor by improving the driving voltage of the motor, thereby reducing the temperature of cold air blown out by the household appliance.

Description

Household appliance capable of providing cold air, driving circuit and permanent magnet direct current motor thereof

Technical Field

The invention relates to a household appliance, a driving circuit and a permanent magnet direct current motor thereof, wherein the household appliance can provide cold air for a blower, a hand dryer and the like.

Background

In daily life, a hair dryer is often used for hair drying operation or hairdressing treatment, a permanent magnet direct current motor of the hair dryer drives fan blades to rotate, air is sucked from an air inlet, and centrifugal airflow formed by the air suction is blown out from a front nozzle of an air duct. When air passes through, if a heating resistor arranged on a heating bracket in the air nozzle is electrified and heated (hot air mode), hot air is blown out; if the selection switch does not energize the heating resistor to heat (cold air mode), cold air is blown out.

A permanent magnet dc motor in a hair dryer generally has a varistor for suppressing sparks, which cannot suppress sparks at a high voltage due to its own characteristics, and thus the driving voltage that the permanent magnet dc motor can withstand is generally 36V or less. However, the blower has a problem that the temperature of the cool air blown out by the blower in the cool air mode is relatively high, which is about 17 degrees celsius higher than the room temperature.

Disclosure of Invention

In view of the above, it is desirable to provide a permanent magnet dc motor capable of withstanding a relatively high driving voltage, a driving circuit of a household appliance using the motor for providing cool air, and a hair dryer having the driving circuit of the household appliance.

The invention provides a household appliance driving circuit capable of providing cold air, which comprises a permanent magnet direct current motor, a rectifier and a divider resistor, wherein one end of the divider resistor is connected with a first input end of the rectifier, the other end of the divider resistor is used for connecting a first end of an alternating current power supply, a second input end of the rectifier is used for connecting a second end of the alternating current power supply, an output end of the rectifier is connected with the permanent magnet direct current motor so as to drive the permanent magnet direct current motor, the permanent magnet direct current motor comprises a stator and a rotor, the rotor comprises a rotating shaft and a commutator fixed on the rotating shaft, the commutator comprises a plurality of commutator segments, the stator comprises electric brushes in sliding contact with the commutator, the household appliance driving circuit is characterized in that the permanent magnet direct current motor further comprises a plurality of capacitors, each capacitor comprises a first electrode and a second electrode, the first electrodes of the plurality of capacitors are electrically connected together, the second electrodes of the capacitors are respectively and electrically connected to a corresponding commutator segment, and the permanent magnet direct current motor is driven under the direct current voltage of 50V to 100V.

Preferably, the rotor further includes a rotor core and a rotor winding, the rotor core is fixed on the rotating shaft, and the rotor winding is wound on the rotor core.

Preferably, the household appliance is a hair dryer or a hand dryer.

Preferably, the permanent magnet dc motor further includes a printed circuit board, the capacitors are disposed on the printed circuit board, the number of the capacitors is the same as the number of the commutator segments, the printed circuit board is annular and disposed on the outer side of the commutator or disposed on one side of the commutator along the axial direction.

Preferably, the capacitor is a chip capacitor, epoxy resin is coated on two ends of the capacitor, the surface of the capacitor on the printed circuit board is provided with the capacitor, and insulating oil is coated on the capacitor.

Preferably, the printed circuit board has the one side orientation of electric capacity the rotor magnetic core, and the another side orientation the commutator, each commutator segment includes a couple, printed circuit board the another side be equipped with a plurality of respectively with the commutator segment that corresponds or couple welded fixed pad, the second electrode of each electric capacity is connected respectively to a plurality of fixed pad.

Preferably, a common test point is arranged on the surface of the printed circuit board, and the common test point is electrically connected with the first electrodes of the capacitors.

Preferably, the driving voltage of the permanent magnet direct current motor is between 60V and 80V.

Preferably, the rotor further includes a rotor magnetic core and a rotor winding, the rotor magnetic core is fixed on the rotating shaft, the rotor winding is wound on the rotor magnetic core, and the wire diameter of the rotor winding is between 0.1mm and 0.45 mm.

Preferably, the outer diameter of the casing of the stator is between 27mm and 37mm, and the outer diameter of the rotor magnetic core is between 16.9mm and 24.4 mm.

Preferably, the commutator has an outer diameter of 6mm to 8mm, and the content of copper in the brush is less than 20%.

Preferably, the capacitance value of the plurality of capacitors is between 1 μ f and 20 μ f.

The invention also provides a household appliance capable of providing cold air, which comprises the household appliance driving circuit.

Preferably, the household appliance is a hair dryer or a hand dryer, and further comprises a fan blade driven by the permanent magnet direct current motor to rotate.

The invention also provides a permanent magnet direct current motor, which comprises a stator and a rotor, wherein the rotor comprises a rotating shaft and a commutator fixed on the rotating shaft, the commutator comprises a plurality of commutator segments, the stator comprises electric brushes in sliding contact with the commutator, the permanent magnet direct current motor further comprises a plurality of capacitors, each capacitor comprises a first electrode and a second electrode, the first electrodes of the capacitors are electrically connected together, the second electrodes of the capacitors are respectively and electrically connected with a corresponding commutator segment, and the permanent magnet direct current motor adopts the capacitors to absorb high-frequency sparks, so that the permanent magnet direct current motor can be driven under the direct current voltage of 50V to 100V.

Compared with the prior art, the permanent magnet direct current motor adopts the capacitor to absorb high-frequency sparks. The capacitor can inhibit sparks generated by the motor in high driving voltage commutation due to the charging and discharging characteristics of the capacitor, so that the driving voltage of the motor can be increased to 50V-100V, and the voltage born by two ends of the voltage dividing resistor is remarkably reduced. Through reducing the voltage at divider resistance both ends, can make the electric current that flows through divider resistance reduce, divider resistance's the reduction that generates heat to the temperature that makes domestic appliance blow out the cold wind is showing to be reduced compared in prior art.

Drawings

In the drawings:

fig. 1 is a side view of a rotor of a dc motor according to a preferred embodiment of the present invention.

Fig. 2 is a schematic view of the top surface of the printed circuit board of fig. 1.

Fig. 3 is a schematic view of the top surface of the printed circuit board of fig. 2 without the capacitor mounted thereon.

Fig. 4 is a schematic view of the bottom surface of the printed circuit board of fig. 1 without the capacitor mounted thereon.

Fig. 5 is a plan view of a rotor of the dc motor shown in fig. 1.

FIG. 6 is a circuit of one embodiment of the rotor winding to capacitor connection.

Fig. 7 is a driving circuit diagram of a preferred embodiment of the household appliance of the present invention.

Description of the main elements

The following detailed description will further illustrate the invention in conjunction with the above-described figures.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without any inventive step based on the embodiments of the present invention, are within the scope of the present invention. It is to be understood that the drawings are provided solely for the purposes of reference and illustration and are not intended as a definition of the limits of the invention. The dimensions shown in the figures are for clarity of description only and are not to be taken in a limiting sense.

It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

It should be noted that the terms of orientation such as up, down, top, bottom, etc. in the present embodiment are only relative to each other or are referred to the normal use state of the product, and should not be considered as limiting.

The household electrical appliance is an electrical appliance with a cold air blowing function, such as a blower, a hand dryer and the like, and can comprise a driving circuit and a fan blade. Please refer to fig. 7, which is a driving circuit diagram of a home appliance according to a preferred embodiment of the present invention. The household appliance driving circuit comprises a rectifier 80, a voltage division resistor R1, a heating resistor R2 and a permanent magnet direct current motor 10. The permanent magnet direct current motor 10 is used for driving the fan blades to rotate. The first end of an alternating current power supply Uac is connected with the first input end 81 of the rectifier 80 through the voltage dividing resistor R1, the second input end 82 of the rectifier 80 is connected with the second end of the alternating current power supply Uac, the output ends 83 and 84 of the rectifier 80 are connected with the permanent magnet direct current motor 10, and the first end of the alternating current power supply Uac is also connected with the second end of the alternating current power supply Uac through the heating resistor R2 and a mode control switch 88. The mode control switch 88 is used to control a hot mode, such as a hot air mode or a cold air mode, of the home appliance, and when the mode control switch 88 is closed, the home appliance is switched to the hot air mode, and when the mode control switch 88 is turned off, the home appliance is switched to the cold air mode. The amplitude of the ac power source Uac may be between 100V-240V, for example 125V, 230V.

Referring to fig. 1, a rotor of a permanent magnet dc motor (hereinafter referred to as a motor) according to a preferred embodiment of the present invention is shown, where the motor 10 includes a stator (not shown) and a rotor. The stator comprises a machine shell, a magnet arranged on the inner wall of the machine shell, an end cover and an electric brush fixed on the end cover. The rotor includes a rotation shaft 20, a rotor core 30, a rotor winding, a commutator 40, and a printed circuit board 50. The rotor core 30 and the commutator 40 are fixed on the rotating shaft 20, and the rotor core 30 may be formed by laminating a plurality of lamination sheets 32. The rotor core 30 includes a plurality of rotor poles, and the rotor winding includes a number of winding units 33 (see fig. 6) corresponding to the number of rotor poles, and each winding unit 33 is wound on a corresponding rotor pole. It is understood that each winding unit 33 may be wound on one rotor pole or may be wound on a plurality of rotor poles.

The commutator 40 includes an insulating base and a plurality of commutator segments 42. In this embodiment, the number of the segments 42 corresponds to the number of rotor poles. The insulating base is made of plastic such as phenolic plastics or nylon molding, the commutator segments 42 are distributed on the insulating base at intervals along the circumferential direction, an insulating groove 44 is arranged between every two adjacent commutator segments 42 to realize electric isolation, and the commutator segments 42 are used for being in sliding contact with a brush of a motor. Each of the segments 42 is further provided with a hook 420 at one end, and the hook 420 is used for electrically connecting with the rotor winding, that is, the terminal 330 (refer to fig. 5 and 6) of the winding unit 33 is wound at the hook 420. The brush is in sliding contact with the commutator 40 to effect commutation.

Referring to fig. 2, fig. 2 is a schematic diagram of a top surface of the printed circuit board 50. The printed circuit board 50 is a ring-shaped board, preferably a circular ring, and has a through hole 52 at the center thereof for the rotation shaft 20 to pass through. In this embodiment, the printed circuit board 50 is mounted on the outer side of the commutator 40. In other embodiments, the printed circuit board 50 may be mounted on one side of the commutator in the axial direction. The top surface of the printed circuit board is provided with a number of capacitors 60 corresponding to the commutator segments 42 for absorbing high-frequency sparks generated during commutation. Each capacitor 60 includes a first electrode 61 and a second electrode 62, the first electrodes 61 of the capacitors 60 are electrically connected together, and the second electrodes 62 of the capacitors 60 are electrically connected to a corresponding segment 42.

The permanent magnet dc motor 10 of the present invention employs a capacitor 60 to absorb high frequency sparks. The capacitor 60 can suppress the spark generated by the commutation of the motor 10 at a high driving voltage due to the charging and discharging characteristics thereof, so that the driving voltage of the motor 10 can be increased to 50V-100V, preferably 60V-80V, and the voltage received at both ends of the voltage dividing resistor R1 can be significantly reduced. By reducing the voltage across the voltage dividing resistor R1, the current flowing through the voltage dividing resistor R1 can be reduced, and the heat generation of the voltage dividing resistor R1 can be reduced, so that the temperature of the cool air blown out by the household appliance can be significantly reduced compared with the prior art. Compared with the prior art, the motor 10 of the embodiment of the invention can control the cold air temperature of the household appliance (such as a blower) to be only 10 ℃ higher than the room temperature.

In this embodiment, the wire diameter of the rotor winding is between 0.1mm and 0.45 mm. The outer diameter of the shell of the stator is between 27mm and 37mm, and the outer diameter of the rotor magnetic core is between 16.9mm and 24.4 mm. The outer diameter of the commutator is between 6mm and 8mm, and the content of copper in the brush is lower than 20%. The capacitance value of the capacitor 60 ranges between 1 μ f and 20 μ f.

Referring to fig. 2 again, the capacitors 60 are arranged at intervals along the circumferential direction, in this embodiment, the axis of the capacitor 60 is substantially along the circumferential tangential direction, and in other embodiments, the axis of the capacitor 60 may be arranged along the radial direction of the printed circuit board. The capacitor 60 is preferably a patch capacitor, and includes a first electrode 61 and a second electrode 62 (see fig. 6).

Referring to fig. 3, fig. 3 is a schematic diagram of a top surface of the printed circuit board shown in fig. 2 when the capacitors 60 are not mounted thereon, the top surface of the printed circuit board 50 is provided with capacitor mounting areas 550 corresponding to the number of the capacitors 60, and each capacitor mounting area 550 is provided with a first capacitor pad 551 and a second capacitor pad 552 at an interval.

Referring to fig. 4, fig. 4 is a schematic view of the bottom surface of the printed circuit board 50 shown in fig. 1 when the capacitor 60 is not mounted, and the bottom surface of the printed circuit board 50 is provided with connection pads 53 and a number of fixing pads 58 corresponding to the commutator segments 42. The printed circuit board has a plurality of first vias 571 and a plurality of second vias 572, the first vias 571 pass through the printed circuit board 50 to electrically connect the connection pads 53 and the first capacitor pads 551, and the second vias 572 pass through the printed circuit board 50 to electrically connect the fixing pads 58 and the second capacitor pads 552. Preferably, the connection pad 53 may be an annular pad disposed along the outer periphery of the printed circuit board, and a common test point 531 is further disposed on the connection pad 53, where the common test point 531 is preferably disposed between any two first vias 571, and is used to test whether the circuit of the printed circuit board 50 is open, short, and the capacitor 60 is normal. The fixing pad 58 is in a fan-shaped ring shape and is disposed on the bottom surface of the printed circuit board 50 near the inner periphery of the printed circuit board 50. It will be understood by those skilled in the art that the shape of the connection pad 53 is not limited to a circular ring shape, and in other embodiments, the connection pad 53 may be a part of a circular ring shape or other shapes such as a zigzag shape, as long as all the first vias 571 can be electrically connected.

Referring to fig. 1-5, the first electrode 61 of the capacitor 60 is soldered to the first capacitor pad 551, and the second electrode 62 of the capacitor 60 is soldered to the second capacitor pad 552 to mount the capacitor 60 on the pcb 50. The capacitor 60 is coated with epoxy resin at both ends thereof for insulating and fixing the capacitor 60, and the top surface of the printed circuit board 50 and the capacitor 60 are coated with insulating oil for moisture protection, heat insulation and insulation. The printed circuit board 50 has a capacitor facing the rotor core 30 and a capacitor facing the commutator 40, and the fixing pad 58 is connected to the hook 420 of the corresponding commutator segment 42 by soldering or bonding.

Referring to fig. 6, which is a circuit diagram of an embodiment of connection between rotor windings and capacitors 60, the terminals 330 of all winding units 33 are connected to hooks corresponding to the commutator segments to form the circuit shown in fig. 6, the second electrode 62 of each capacitor 60 is connected to the commutator segment 42 through the second via 572 and the fixed pad 58, and the first electrode 61 of each capacitor 60 is connected to the connection pad 53 through the first via 571, such that the capacitor 60 is connected between the terminals 330 of the winding units 33 and the connection pads 53. When the motor is operated, the brush is in sliding contact with the commutator 40 for commutation, and the capacitors 60 absorb high-frequency sparks generated during commutation to prevent the current sparks from corroding the brush and the commutator 40.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.

Claims

1. A household appliance driving circuit capable of providing cold air comprises a permanent magnet direct current motor, a rectifier and a divider resistor, wherein one end of the divider resistor is connected with a first input end of the rectifier, the other end of the divider resistor is used for being connected with a first end of an alternating current power supply, a second input end of the rectifier is used for being connected with a second end of the alternating current power supply, an output end of the rectifier is connected with the permanent magnet direct current motor, the permanent magnet direct current motor comprises a stator and a rotor, the rotor comprises a rotating shaft and a commutator fixed on the rotating shaft, the commutator comprises a plurality of commutator segments, the stator comprises electric brushes in sliding contact with the commutator, the household appliance driving circuit is characterized in that the permanent magnet direct current motor further comprises a plurality of capacitors, each capacitor comprises a first electrode and a second electrode, the first electrodes of the plurality of capacitors are electrically connected together, and the second electrodes of the plurality of capacitors are respectively and electrically connected with a corresponding commutator segment, the permanent magnet direct current motor is driven under the direct current voltage of 50V to 80V, the outer diameter of the commutator is 6mm to 8mm, and the outer diameter of the rotor magnetic core is 16.9mm to 24.4 mm.

2. The driving circuit for household electrical appliances according to claim 1, wherein the rotor further comprises a rotor core fixed to the rotation shaft and a rotor winding wound around the rotor core.

3. The household appliance driving circuit according to claim 2, wherein the household appliance is a hair dryer or a hand dryer, and the number of the commutator segments is 5.

4. The driving circuit of a household electrical appliance according to claim 2, wherein the permanent magnet dc motor further comprises a printed circuit board, the capacitors are disposed on the printed circuit board, the number of the capacitors is the same as the number of the commutator segments, and the printed circuit board is annular and disposed outside the commutator or disposed on one side of the commutator along an axial direction.

5. The driving circuit of a home appliance according to claim 4, wherein the capacitor is a chip capacitor, both ends of the capacitor are coated with epoxy resin, the surface of the printed circuit board provided with the capacitor and the capacitor are coated with insulating oil.

6. The driving circuit of household electrical appliance according to claim 4, wherein the printed circuit board has a capacitor side facing the rotor core and a capacitor side facing the commutator, each of the commutator segments includes a hook, the other side of the printed circuit board is provided with a plurality of fixing pads respectively soldered to the corresponding commutator segment or the hook, and the plurality of fixing pads are respectively connected to the second electrodes of the capacitors.

7. The household appliance driving circuit according to claim 4, wherein the printed circuit board has a common test point on a surface thereof, the common test point being electrically connected to the first electrodes of the plurality of capacitors.

8. The household appliance driving circuit according to claim 2, wherein the driving voltage of the permanent magnet dc motor is between 60V and 80V.

9. A household appliance drive circuit as claimed in claim 2, wherein the wire diameter of the rotor winding is between 0.1mm and 0.45 mm.

10. A driving circuit of a household appliance according to claim 2, wherein the outer diameter of the casing of the stator is between 27mm and 37 mm.

11. The driving circuit of a household appliance according to claim 2, wherein the capacitance of the plurality of capacitors is between 1 μ f and 20 μ f.

12. A cold-wind-supplying home appliance comprising the home appliance driving circuit of any one of claims 1 to 11.

13. The household appliance of claim 12, wherein the household appliance is a hair dryer or hand dryer, further comprising a fan blade driven to rotate by the permanent magnet dc motor.

14. A permanent magnet direct current motor for a household appliance driving circuit for providing cold air comprises a stator and a rotor, wherein the rotor comprises a rotating shaft and a commutator fixed on the rotating shaft, the commutator comprises a plurality of commutator segments, the stator comprises an electric brush in sliding contact with the commutator, and the permanent magnet direct current motor is characterized in that the permanent magnet direct current motor further comprises a plurality of capacitors, each capacitor comprises a first electrode and a second electrode, the first electrodes of the capacitors are electrically connected together, the second electrodes of the capacitors are respectively and electrically connected to a corresponding commutator segment, the permanent magnet direct current motor adopts the capacitors to absorb high-frequency sparks, so that the permanent magnet direct current motor can be driven under the direct current voltage of 50V to 80V, the outer diameter of the commutator is 6mm to 8mm, and the outer diameter of a magnetic core of the rotor is 16.9mm to 24.4 mm.

15. The permanent magnet dc motor of claim 14 wherein said rotor further comprises a rotor core and a rotor winding, said rotor core being secured to said shaft, said rotor winding being wound around said rotor core.

16. The pm dc motor of claim 15, further comprising a pcb, wherein said plurality of capacitors are disposed on said pcb, and wherein said plurality of capacitors are equal in number to said plurality of segments, and said pcb is annular and disposed on an outer side of said commutator or on a side of said commutator in an axial direction.

17. The permanent magnet dc motor of claim 16 wherein the wire diameter of the rotor winding is between 0.1mm and 0.45mm and the outer diameter of the stator housing is between 27mm and 37 mm.

18. The permanent magnet dc motor of claim 16, wherein the printed circuit board has a capacitor side facing the rotor core and a capacitor side facing the commutator, each of the segments includes a hook, the other side of the printed circuit board has a plurality of fixing pads soldered to the corresponding segments or hooks, and the plurality of fixing pads are connected to the second electrodes of the capacitors, respectively.

19. The permanent magnet dc motor of claim 15 wherein the number of segments is 5.