KR960014255B1 - Tub breaking apparatus and the method for a washing machine - Google Patents

Abstract

The apparatus reduces the time interval necessary for stopping the basin and decreases noise and wear of the brake mechanism by applying various brake methods according to spinning speed. The apparatus consists of : a filter(11) which makes AC power with constant voltage; a rectifier(12) which converts AC to DC; a contoller(16) which outputs signals to the braking circuit and a base driver; a braking circuit(13) supplying motor with current; an inverter(14) which drives the motor with the current from the braking circuit; a current sensor(15) which senses the current from the braking cicuit to send to the inverter; a base driver(17); and a motor position sensor(18) which sends the position of the motor to the controller.

Description

Dehydration tank braking device and method of washing machine

1 is a schematic internal structure of a conventional washing machine.

2 is an explanatory view of the brake located in the clutch of FIG.

Figure 3 is a block diagram of a dehydration tank braking apparatus of the present invention washing machine.

4 is a dehydration tank speed waveform at the time of dehydration in FIG.

5 is a configuration diagram of a dehydration tank braking device of the washing machine of the present invention.

6 is a detailed circuit diagram of the braking circuit section in FIG. 5, (a) is a detail diagram of the braking circuit section in the use of power generation braking, and (b) is a detail diagram of the braking circuit section in the use of sacrificial braking.

7 is an explanatory diagram of operations according to each braking method of the motor in the present invention.

8 is a flowchart illustrating a method for braking a dehydration tank of the washing machine of the present invention.

9 is a circuit diagram of a braking circuit section and an inverter when a BLDC motor is used in the present invention.

10 is an operation waveform diagram of a switching device according to a braking method when using a BLDC motor in the present invention.

* Explanation of symbols for main parts of the drawings

1: outer tank 2: dehydration tank

3: stirrer 4: clutch

5: dewatering 6: washing shaft

7: motor 8: drive pulley

9: driven pulley 10: V-belt

11 filter unit 12 rectifying unit

13: braking circuit part 13-1: overvoltage protection part

13-2: discharge control unit 14: inverter unit

15: current sensing unit 16: base driving unit

17: control unit 18: motor position detection unit

The present invention is intended to shorten the braking time during braking of the dehydrating tank of the washing machine. In particular, the braking time of the braking time is changed by changing the braking method according to the motor speed during braking to prevent noise and mechanical wear caused by using the mechanical brake. It relates to a dehydration tank braking apparatus and method of the washing machine to improve the reliability of each rotating element while maintaining a short.

The internal structure of the conventional washing machine is installed so that the dehydration tank (2) is rotatable inside the outer tub (1), as shown in Figure 1, the pulsator (3) is installed on the inner bottom of the dehydration tank (2) The dehydration tank 2 and the pulsator 3 are fastened to the dehydration shaft 5 and the washing shaft 6, respectively, and the driving pulley 8 of the motor 7 installed on the lower side of the outer tub 1 And the driven pulley (9) of the clutch (4) is installed so that power is transmitted to the clutch (4) via the V belt (10).

As shown in FIG. 2, the brake located at the clutch 4 has a brake lining 3 'connected to the outer circumferential surface of the brake drum 1' by a predetermined angle, and the brake lining 3 One side of ') is fixed to the band fixing part 7' fixed to the clutch through the brake band 2 ', and the other side of the brake lining 3' is connected to the brake band 2 '. The brake lever 4 'is coupled to one band pin 6' to be movable.

Here, reference numeral 5 'is a lever pin, 8' is a torsion coil spring.

Looking at the prior art configured as described above, the brake of the washing machine is a brake drum (1 ') fixed to the dewatering shaft (5) a rotating torque transmitted to the dewatering shaft (5) in accordance with the rotation of the pulsator (3) during washing ) And the dehydration shaft 5 is prevented from rotating by offsetting the friction torque between the brake lining 3 'and the dehydration shaft 5 when the dehydration shaft is released. When the brake is applied again when dehydration is performed, the brake lining 3 'constrains the brake drum 1' to perform a braking operation.

In order to release the restraint of the brake drum 1 'during dehydration, the brake lever 4' is driven to relax the brake lining 3 'where one end of the brake lever 4' is fixed with a brate pin. The dehydration shaft 5 integrated with 1 ') becomes rotatable to perform dehydration.

If the brake lever 4 'is driven and stopped when the dehydrator rotates suddenly after a predetermined dehydration, the free end of the brake lining 3' attached to one end of the brake lever 4 'is moved by a predetermined distance. In reverse movement, the brake lining 3 'constrains the brake drum 1' and performs the brake operation.

However, in this conventional technique, the braking force decreases gradually with the wear life of the washing machine due to the wear of the brake drum, and the reliability decreases. The mechanism of the clutch having the brake structure is complicated by the use of the mechanical brake. The manufacturing cost rises, wear debris enters the other structure of the clutch due to wear of the brake drum, there is a problem that it is difficult to secure the reliability of the clutch operation.

Therefore, in order to solve the conventional problems, the present invention applies the power to the motor to rotate the motor to rotate the dehydration tank while turning off the power of the motor to stop the dehydration tank when the user stops the lid of the washing machine before the dehydration tank When the motor is opened, it detects the motor speed and current at the time and brakes by sacrificial braking and reverse braking to keep the braking time short while maintaining the safety of the washing machine. When described in detail with reference to the drawings as follows.

3 is a block diagram of the dehydration tank braking device of the washing machine of the present invention, as shown therein, a rotatable dehydration tank 2 is installed inside the outer tank 1, and the forward rotation and A pulsator (3) capable of reverse rotation is installed, and the washing shaft (6) for transmitting rotational force to the center of the pulsator (3) is configured in series with the motor (7).

In addition, the dehydration tank braking device configuration diagram of the washing machine for controlling the motor 4 is a filter unit 11 for filtering and outputting the AC power input to a predetermined value, as shown in FIG. 5, and the filter unit 11 Rectification part 12 rectifying and smoothing the voltage through the DC voltage) and braking for supplying a current to the motor to have a rotational force in a direction opposite to the rotation direction of the motor 7 by the DC voltage input from the rectifier 12 The circuit section 13, the inverter section 14 for driving the motor 7 according to the current supplied from the braking circuit section 13, and the current supplied from the braking circuit section 13 to the inverter section 14 The current sensing unit 15 for sensing the amount, the base driving unit 17 for driving the transistor of the inverter unit 14 in accordance with a control signal, and the signal for controlling the rotation state of the motor 7 the braking Control output to circuit section 13 and base drive section 17 It shall consist of 16, and a motor position detecting section 18 that detects the rotation position of the motor 7 is output to the control unit 16.

Referring to the operation and effects of the present invention configured as described above in detail.

When AC power is applied, the filter is filtered by the filter 11, rectified and smoothed through the bridge diode BD and the smoothing capacitor C, and converted to a DC voltage to be output to the braking circuit unit 13. At this time, when washing or dehydration is not braking, the control unit 16 outputs a control signal to the brake circuit unit 13 to prevent braking and sends a driving signal to the base driving unit 17.

Accordingly, the braking circuit 13 supplies the DC voltage input from the rectifying section 12 to the inverter section 14. As described above, the inverter unit 14 receiving the base driving signal from the base driving unit 17 while the DC voltage is supplied from the rectifying unit 12 causes the motor 7 to rotate.

As the motor 7 rotates, as the rotational force is transmitted to the center of the pulsator 3 by the washing shaft 6 connected in series with the motor 7, washing and dehydration are performed by the pulsator 3. Here, when washing, the dehydration shaft (5) is separated from the washing shaft (6) so that the dehydration tank (2) does not rotate during washing, and when dehydration, the dehydration shaft (5) is combined with the washing shaft (6) and dewatered. The jaw 2 rotates.

In the dehydration, the dehydration shaft 5 coupled to the washing shaft 6 is rotated during dehydration as described above, and when the dehydration is completed and the power of the motor 7 is cut off, the inertia force of the dehydration tank 2 is reduced. As shown in the curve P of FIG. 4, it takes T _do until the dehydration tank 2 stops. Before this time T _do is reached, the user opens the lid of the washing machine and moves his hand into the dehydration tank 2. If you put it in, the finger may get caught in the hole of the dehydration tank and the finger may be damaged or the hand may be twisted in the laundry. If you open the lid during dehydration, the braking time should be shortened to reach the Q curve of FIG.

Therefore, in the present invention, the braking time of the dehydration tank is shortened by generating reverse torque in the motor during braking.

In FIG. 6, the resistance R _M and the counter electromotive force E _M are the equivalent circuits of the motor 7, and when the counter electromotive force E _M and the current i _M are in the direction, the motor 7 rotates in the rotational direction. Torque is in the direction of current, and in the direction of current (i ' _M ), it is in the reverse direction of torque.

When the motor 7 normally motors, the motor current flows through the transistors Q1 and Q4 of the inverter unit 14 shown in FIG. 6, which constitutes a circuit as shown in FIG.

In the case of braking the motor 7 which normally rotates as in the above, for example, at the time of power generation braking, the circuit configuration of the braking circuit part 13 is the same as in (a) of FIG. During power generation braking, the movable terminal (c) of the switch (S1) is switched to the fixed terminal (b), and the flowing motor current is in the same state as in (b) of FIG. 7 so that the reverse phase current (i ' _M ) i' _M = It flows to (E _M / R _d + R _M ) and generates reverse torque (T = -Ki ' _M : K is the motor constant). And this consumes the energy generated by using the braking resistor (Rd).

The method shown in (c) of FIG. 7 consumes through the resistor R _M in the motor 7. At this time, the transistor Q2 is turned on so that a current flows through the transistor Q2 and the diode D4.

On the other hand configuration when to braking by using a sacrificial braking in circuit as in claim 6 degrees and (b) The operation is as in claim 7 ° (d) a current (i _'M) of the motor is charged to the capacitor (C _o) do. If the charging voltage of the capacitor (C _o ) is higher than or equal to, there is a possibility that the capacitors and the transistors of the power element may be damaged. If the charging voltage of the capacitor is higher than the set value, the resistors (R1, R2, R3) in FIG. And the transistor Qr is operated through the comparator OP1 to discharge the electric charge charged in the capacitor C _o through the discharge resistor Rr to lower the voltage.

Reversed braking is obtained by increasing the applied voltage to the motor 7 in reverse and obtaining a high braking force. The circuit configuration at this time is as shown in (e) of FIG. 7 and the current i ' _M = (V _co + E _M ) / (R _M + R _S ) for sacrificial braking i ' _M = (E _M -V _co ) / (R _M + R _S ) or for power generation braking (i' _M = E _M / (R _M + R _d + R _S ) A current higher than) flows. On the other hand, if this current is any abnormality, the switch may be damaged, so a countermeasure is required.

Accordingly, the present invention uses the braking algorithm as shown in FIG. 8 to shorten the braking time and prevent breakage of the switching element by overcurrent. That is, when it is detected that the lid is opened during dehydration, the motor is braked. At this time, if the motor speed is higher than the set speed (W _o ), the back electromotive force of the motor is large so that the braking force is applied to the motor by the operation of sacrificial braking. If it is lower than (W _o ), the sacrificial braking and reverse braking are repeated according to the amount of current flowing through the motor.

When using the method described in the flowchart of FIG. 8 and employing the BLDC motor as the motor 7, the circuit shown in FIG. 9 is composed of resistors R1, R2, R3, comparator OP1 and braking resistor Rr. The operation of the overvoltage protection unit is the same as described above. Here, only the operating states of the switching elements Q1 to Q6 in the case of sacrificial braking and reverse braking.

If the voltages (E _a , E _b , E _c ) of each phase of the BLDC motor are the same as those in (a) of FIG. 10, the transistors Q1 to the same pulse waveform as in (b) of FIG. Q6) is controlled. When the rotational force in the reverse direction is obtained, the same operation as in (c) of FIG. 10 is performed. When sacrificial braking is turned off, the inertia energy of the dehydration tank is sacrificed to the condenser C _o through the diodes D1 to D6 of FIG. 9 according to each state.

In the case of using a three-phase BLDC motor as shown in FIG. 9, proper braking time and braking current can be secured by repeating sacrificial braking and reversed braking using the flow chart of FIG.

As described in detail above, when the washing machine lid is opened during dehydration, the motor speed and the current flowing through the motor are sensed so that there is no mechanical brake by using the sacrificial braking and reverse braking method, thereby reducing the overall material cost by eliminating mechanical wear and noise. It works.

Claims (4)

Filter unit 11 for filtering the input AC power to a constant voltage, rectifying unit 12 for rectifying and smoothing the voltage through the filter unit 11 to the DC voltage, washing operation of the washing machine or The control unit 16 outputs a control signal for driving and braking the motor 7 during braking. When the DC voltage is input from the rectifying unit 12 and the braking signal is applied from the control unit 16, the motor 7 The brake circuit unit 13 supplies a current to the motor to have a rotation force in a direction opposite to the rotation direction, and the motor 7 rotates in a rotational direction and in a reverse direction according to the input base drive signal and the brake signal from the brake circuit unit 13. An inverter unit 14 driving in a direction, a current sensing unit 15 which senses a current flowing in the motor 7 and outputs it to the controller 16, and the inverter unit according to a driving signal of the controller 16. Base driving the transistor in (14) ET 17, a dewatering aid such device of a washing machine consisting of a motor position detecting section 18 and outputting the detection to the control unit 16 the position of the motor 7. 2. The brake circuit unit (13) according to claim 1, wherein the braking circuit unit (13) comprises a switch (S1) for switching and selecting when braking when generating braking and non-braking, and a braking resistor (Rd) for generating and braking the motor (7). A dehydration tank braking device for a washing machine. The method of claim 1, wherein the braking circuit 13 is a capacitor for use sacrificial braking sacrifice (C _o) and, said sacrificial capacitor (C _o) over-voltage for the charging voltage remains below a predetermined voltage to the protecting portion (13 1), the sacrificial capacitor (C _o) the discharge control unit (13-2) to maintain the predetermined voltage when the charging voltage is a predetermined voltage or more to the discharge, depending on the output signal of the over-voltage protection unit (13-1) for the Dehydration tank braking device of the washing machine, characterized in that consisting of. A first step of detecting whether the washing machine lid is open during dehydration; a second step of detecting the speed of the motor if the lid is opened in the first step; and sacrificial braking if the motor speed detected in the second step is greater than the set speed. The third step of detecting the current flowing through the motor if the operation speed is less than the set speed, and the fourth step of operating the sacrificial braking if the current sensed in the third step is greater than the set current, and operates in reverse phase braking if it is smaller than the set current. Braking method of the washing machine dehydration tank, characterized in that made.