CN201095696Y - Drum washing machine - Google Patents

Abstract

The utility model provides a washing machine, which comprises: a drum for storing laundry; a motor for rotating the drum; and a driving part for driving the motor. The drive unit drives the motor by supplying a DC current to the motor during the washing operation, and drives the motor by supplying an AC current to the motor during the spin-drying operation. The washing machine can suppress the temperature rise of the motor and prolong the life of the motor.

Description

front load washing machine

technical field

The utility model relates to a drum type washing machine.

Background technique

In the existing drum-type washing machine, the microcomputer reads the rotational speed of the motor according to the output of the tachometer (tachometer sensor) installed on the motor, calculates the difference between the read rotational speed and the target rotational speed, and determines the triac (triac ) (Bidirectional Thyristor) firing angle, using phase control to provide the necessary voltage and supply it to the motor, thereby controlling the speed of the motor.

In JP-A-7-303787, the AC current output from the triac is supplied to the motor as it is. The method of driving the motor with AC current can be realized with a simple structure, but the efficiency of motor control is poor due to the back electromotive force generated when the current direction is switched during washing operation. Therefore, the temperature of the motor rises significantly, so a large motor has to be used.

In Japanese Patent Application Laid-Open No. 8-309077, an AC current output by a triac is converted into a DC current by a rectification circuit formed of a diode bridge, and the DC current is supplied to a motor. The method of driving the motor with DC can use the flywheel diode (flywheel diode) that releases the counter electromotive force, and can drive the motor efficiently and reduce the temperature rise of the motor. However, since the direction of the current flowing through the carbon brushes of the motor does not change, for example, when the motor rotates at high speed in one direction during dehydration, only one brush of the motor is worn due to the polarity of the brushes of the motor. Since the amount of wear on the brush during dehydration is very large, which is ten times that during washing, if only one side is worn during dehydration, it will have a great impact on the life of the motor. Moreover, the drive using direct current will generate relatively large radio noise during dehydration.

Utility model content

The washing machine of the present invention includes: a drum for storing laundry; a motor for rotating the drum; and a drive unit for driving the motor. The drive unit drives the motor by supplying a DC current to the motor during the washing operation, and drives the motor by supplying an AC current to the motor during the spin-drying operation.

In this washing machine, the temperature rise of the motor can be suppressed, and the life of the motor can be extended.

Description of drawings

Fig. 1A is a cross-sectional view of the front-loading washing machine in Embodiment 1 of the present invention.

FIG. 1B is a circuit diagram of the front-loading washing machine in Embodiment 1. FIG.

Fig. 2 is a circuit diagram of the front-loading-type washing machine at the time of spin-drying in the first embodiment.

FIG. 3 shows the rotation speed of the drum of the front-loading-type washing machine in Embodiment 1. FIG.

Detailed ways

Fig. 1A is a cross-sectional view of front-loading washing machine 1001 in Embodiment 1 of the present invention. FIG. 1B is a circuit diagram of the drum type washing machine 1001 .

Drum type washing machine 1001 includes: a frame body 52 having a door 51; a drum 53 accommodated in the frame body 52; a water supply part 57 for supplying water into the drum 53; The motor 20 ; the drive unit 61 that drives the motor 20 . The pulleys 55 and 56 are fixed to the drum 53 and the motor 20, respectively. A belt 54 is stretched between the pulleys 55 , 56 . Clothes to be washed are stored in drum 53 through door 51 . The electric motor 20 is rotated by the electric current supplied from the drive part 61, rotates the drum 53 via the pulley 56, the belt 54, and the pulley 55, and washes the laundry.

FIG. 1B is a circuit diagram of drive unit 61 of front-loading washing machine 1001 .

The motor 20 has a stator and a rotor. The motor 20 includes: a high-speed winding 1 wound on a stator; a low-speed winding 2 connected in series to the high-speed winding 1 and wound on the stator; and a rotor winding 3 wound on a rotor.

The diode bridge 18 is formed by four diodes 18A and the freewheel diode 17 . The freewheel diode 17 discharges the electric current generated by the counter electromotive force of the motor 20 to smoothly rotate the motor 20 , reduces the electric power supplied to the motor 20 , and suppresses temperature rise.

The control unit 62 detects the rotation speed of the motor 20, determines the firing angle based on the rotation speed, and conducts the triac (bidirectional thyristor) 6 to the firing angle. The triac 6 supplies the AC current supplied from the AC power supply 21 to the motor 20 only at the firing angle. The power relay 7 switches the current from the AC power supply 21 . The AC-DC switching relays 8 and 11 operate as a pair, and switch between the high-speed winding 1 that operates with an alternating current and the low-speed winding 2 that operates with a direct current.

The rotation direction switching relays 9 and 10 operate as a pair to change the rotation direction of the motor 20 . The rotation direction switching relay 10, the rotor winding 3, and the rotation direction switching relay 9 are connected in series.

The AC-DC switching relay 12 operates in conjunction with the start switch for starting washing, and prevents the motor 20 from rotating when the power is turned on. The noise prevention coils 4 and 5 are respectively connected in series with the AC and DC switching relays 8 and 11 to prevent the AC and DC switching relays 8 and 11 from generating noise. The noise preventers 13 to 16 are composed of a resistor and a capacitor connected in series with the resistor, and prevent the triac 6 or the relays 7, 8, 10, 11, and 12 from generating noise.

The AC power supply 21 has output terminals 21A, 21B that output AC current. The diode bridge 18 rectifies the AC current input to the AC input and output terminals 18E, 18F, and outputs DC current from the DC output terminals 18C, 18D. The DC output terminal 18C of the diode bridge 18 has a higher potential than the DC output terminal 18D.

The operation of front-loading washing machine 1001 will be described. FIG. 3 shows the rotational speed of the drum 53 from washing to dehydration in the front-loading washing machine 1001 . The drive part 61 drives the motor 20, and can rotate the drum 53 both left and right. In drum type washing machine 1001 , the ratio of the rotation speed of motor 20 to the rotation speed of drum 53 , that is, the reduction ratio is set to 10.8 by pulleys 55 , 56 and belt 54 .

When the start button is pressed at time TP1, front-loading washing machine 1001 starts operating. When the operation starts, the washing machine 1001 starts the washing process 201 . Motor 20 supplies water and detergent to drum 53 from water supply unit 57 while rotating drum 53 left and right (stroke 101 ). Then, the driving unit 61 drives the motor 20 to rotate the drum 53 approximately uniformly from side to side, and agitates the laundry stored in the drum 53 together with water and detergent (step 102 ). In the stirring stroke 102, the flushing stroke 201 is completed.

After the washing process 201 ends, the washing machine 1001 starts the first rinsing process 202 . The drain unit 58 discharges water and detergent from the drum 53 (step 103), and then the water supply unit 57 supplies water to the laundry using a nozzle (step 104). Then, the driving unit 61 drives the motor 20 to rotate the drum 53 at a high rotation speed of 800 rpm exceeding 420 rpm (step 105 ), and stops the drum 53 while rotating by inertia (step 106 ). Then, water is supplied, and the driving unit 61 drives the motor 20 to rotate the drum 53 approximately uniformly in the left and right, thereby stirring the laundry stored in the drum 53 together with the water (step 107 ).

After the first rinsing course 202 , the washing machine 1001 starts the second rinsing course 203 . The drain 58 drains water from the drum 53 (stroke 108). Then, the driving unit 61 drives the motor 20 to rotate the drum 53 at a high rotation speed of 800 rpm exceeding 420 rpm (step 109 ), and stops the drum 53 while rotating by inertia (step 110 ). Then, water is supplied, and the driving unit 61 drives the motor 20 to rotate the drum 53 substantially uniformly from side to side, and agitates the laundry stored in the drum 53 together with the water (step 111 ).

After the second rinsing process 203 , the washing machine 1001 starts a dehydration process 204 . The drain part 58 drains water from the drum 53 (stroke 112). Then, the driving unit 61 drives the motor 20 to rotate the drum 53 at a high rotation speed of 800 rpm exceeding 420 rpm (stroke 113 ). Then, the drum 53 is stopped while being rotated by inertia (step 114), and the washing of the clothes is completed.

Next, the electric circuit of front-loading-type washing machine 1001 during washing operation and dehydration operation will be described.

Fig. 1B is a circuit diagram of washing machine 1001 during washing operation. The AC-DC switching relays 8 and 11 are switched, and the current flowing from the output terminal 21A of the AC power supply 21 is input to the AC input terminal 18E of the diode bridge 18 via the triac 6 and the noise prevention coil 5 . The current flowing from the output terminal 21B of the AC power supply 21 is supplied to the AC input terminal 18F of the diode bridge 18 via the noise prevention coil 4 . The DC output terminal 18C of the diode bridge 18 is connected to the input side of the rotation direction switching relay 10 , and the DC output terminal 18D is connected to the low-speed winding 2 of the motor 20 . At the same time, the control unit 62 periodically switches the rotation direction relays 9 and 10 to alternately rotate the drum 53 to the left and to the right at a low speed, thereby washing the laundry.

Fig. 2 is a circuit diagram of washing machine 1001 during dehydration operation. The control unit 62 turns on the AC/DC switching relay 12 , switches the AC/DC switching relays 8 and 11 , and supplies the current flowing from the output terminal 21A of the AC power supply 21 to the rotor winding 3 via the triac 6 and the noise prevention coil 5 . In addition, the current flowing from the output terminal 21B of the AC power supply 21 is supplied to the high-speed side winding 1 via the noise prevention coil 4 . Thereby, drum 53 is rotated at a high rotation speed, and the laundry after washing is dehydrated.

During washing shown in FIG. 3 , when rotating drum 53 at a predetermined rotational speed of 420 rpm or less, control unit 62 supplies DC current from drive unit 61 to motor 20 . In addition, during dehydration (strokes 105, 109, 113) shown in FIG. 61 supplies AC current to the motor 20 . Here, since the reduction ratio is 10.8, the predetermined speed of 420 rpm of the drum 53 corresponds to the rotation speed of the motor 20 of 4536 rpm. During periods T1 , T3 , and T5 when the rotational speed of drum 53 is equal to or lower than a predetermined rotational speed (420 rpm), control unit 62 flows DC current from drive unit 61 to low-speed winding 2 to drive motor 20 . Accordingly, the driving unit 61 can efficiently drive the motor 20 . When drive unit 61 increases the rotational speed of drum 53 to a predetermined rotational speed (420 rpm), control unit 62 switches the circuit of washing machine 1001 from the circuit shown in FIG. 1B to the circuit shown in FIG. 2 . As a result, the control unit 62 stops supplying the DC current from the driving unit 61 to the low-speed winding 2 , and flows an AC current from the driving unit 61 to the high-speed winding 1 to drive the motor 20 . When the rotational speed of the drum 53 exceeds a predetermined rotational speed, the control unit 62 flows an AC current from the driving unit 61 to the high-speed coil 1 to drive the motor 20 . Accordingly, during dehydration where the rotation speed of the motor 20 is high and the wear of the carbon brush is large, it is possible to avoid the wear of only one side of the carbon brush and suppress the generation of radio noise. The control unit 62 stops the AC current supply from the drive unit 61 to the high-speed winding 1 so that the drive unit 61 rotates the drum 53 at a speed exceeding a predetermined speed and then stops the rotation (strokes 106 , 110 , 114 ). Thus, the drum 53 rotates by inertia while gradually decreasing its rotational speed.

A high-speed winding 1 and a low-speed winding 2 connected in series to the high-speed winding 1 are wound around the stator of the motor 20 . During periods T1 , T3 , and T5 while drum 53 (motor 20 ) is rotating at a predetermined rotation speed or less, control unit 62 supplies DC current from drive unit 61 to both high-speed side winding 1 and low-speed side winding 2 . During periods T2, T4, and T6 in which the drum 53 (motor 20) rotates at a high rotational speed exceeding a predetermined rotational speed, the control unit 62 supplies an AC current from the drive unit 61 to the high-speed side coil 1 and does not supply AC current to the low-speed coil 1. Side winding 2 supplies any current. According to this configuration, during washing operation in which drum 53 rotates at a low rotational speed, the number of turns of the winding wound on the stator increases, that is, the number of ampere-turns increases, so that driving unit 61 can efficiently drive the motor. During dehydration operation in which the drum 53 rotates at a high rotation speed, the drive unit 61 supplies current only to the high-speed side winding 1, so that the resistance of the winding is reduced and a large current can be supplied, thereby increasing the power of the motor 20.

In drum type washing machine 1001 according to the embodiment, since only one side of the carbon brush of the motor is worn, a small motor can be used and has excellent durability. Therefore, it is not limited to the front-loading washing machine, and can be widely applied to various electric equipment using a general-purpose electric motor.

In addition, this invention is not limited by this embodiment.

Claims (5)

1. A drum type washing machine, which has: Drums for storing laundry; an electric motor to rotate the drum; and a drive section that drives the motor, The drum type washing machine is characterized in that, The drive unit drives the motor by supplying a DC current to the motor during a washing operation, and drives the motor by supplying an AC current to the motor during a dehydration operation. 2. drum type washing machine as claimed in claim 1, is characterized in that, The motor has: stator; a high-speed side winding wound on said stator; and a low-speed side winding wound on the stator and connected in series with the high-speed side winding, The drive unit drives the motor by supplying a DC current to both the high-speed winding and the low-speed winding during washing operation, and supplies only the high-speed winding and the low-speed winding to both the high-speed winding and the low-speed winding during dehydration operation. The high-speed side winding supplies AC current to drive the motor. 3. drum type washing machine as claimed in claim 2, is characterized in that, The drive unit supplies AC current only to the high-speed side winding of the high-speed side winding and the low-speed side winding and does not supply any current to the low-speed side winding during dehydration operation, thereby driving the motor. . 4. drum type washing machine as claimed in claim 1, is characterized in that, The motor rotates at a rotation speed equal to or lower than a predetermined rotation speed during washing operation, and rotates at a rotation speed exceeding the predetermined rotation speed during dehydration operation. 5. A drum type washing machine, which has: Drums for storing laundry; an electric motor to rotate the drum; and a drive section that drives the motor, The drum type washing machine is characterized in that, The drive unit drives the motor by supplying a DC current to the motor when the motor rotates at a rotation speed equal to or lower than a predetermined rotation speed, and supplies a DC current to the motor when the motor rotates at a rotation speed exceeding the predetermined rotation speed. The electric motor supplies alternating current to drive the electric motor.

Images