JP4806436B2 - Washing machine - Google Patents

Description

  The present invention relates to a washing machine, and more particularly, to a washing machine suitable for a vertical washing machine provided with a laundry dewatering tub having an open upper surface that is rotatable about a vertical or inclined axis. In addition, the washing machine said here also includes the washing-drying machine provided with the drying function by a warm air.

  In a general vertical automatic washing machine, a bottomed cylindrical outer tub is suspended and supported by a vibration-absorbing suspension rod. Inside the outer tub, there are a number of dewatering holes in the same shape with a bottomed cylinder. A washing and dewatering tank having a perforated hole is rotatably arranged around a vertical or inclined shaft, and a stirring pulsator (stirring blade) is rotatably provided on the inner bottom of the tank.

  In such a washing machine, the laundry dewatering tank and the pulsator are integrally rotated at a high speed to dehydrate the laundry, and at that time, if there is an unbalance of weight due to the deviation of the laundry around the rotation axis, The washing and dewatering tank vibrates greatly, and the outer tank also swings greatly with this, causing abnormal noise and breakage. Therefore, in general, in order to detect abnormal vibration of the outer tub, a vibration detection lever is provided in the gap between the outer tub and the outer box, and when the outer tub comes into contact with this lever, the rotation of the washing / dehydrating tub is stopped, The imbalance is corrected by rinsing by supplying water into the laundry dewatering tank and rotating the pulsator.

  However, in the case of the method of mechanically detecting vibration as described above, the washing machine is in the middle of increasing the rotation speed of the washing / dehydrating tub even if it is unbalanced so as not to cause a problem when the washing / dehydrating tub is rotated at high speed. There is a tendency that the dehydration operation is interrupted by detecting a large swing that occurs when the resonance point is passed. In order to avoid such erroneous detection, it is necessary to lower the detection sensitivity of the vibration detection lever, and this time, there is a high possibility that the detection of vibration will be missed. Therefore, in order to detect abnormal vibration more reliably and more quickly, conventionally, a method of detecting imbalance by detecting a phenomenon electrically corresponding to the vibration of the washing and dewatering tub has been used in combination. .

  Specifically, if the imbalance is large, the unevenness of the rotational speed of the washing / dehydrating tub becomes large. Therefore, a method for detecting increase / decrease in the rotational speed of the motor (see, for example, Patent Document 1), and an increase / decrease in motor acceleration A method (for example, see Patent Document 2) or a method for detecting a change in the duty ratio of a PWM signal for motor control by inverter drive while the rotation speed of the washing and dewatering tub is maintained substantially constant (for example, Patent Document) 3 etc.) are known.

  However, all of the conventional electrical imbalance detection methods as described above have drawbacks. That is, the rotational speed and acceleration of the motor are detected based on a pulse signal generated by a Hall element attached to the motor, but there is a risk of erroneous detection due to various disturbance factors and product variations. Specifically, in the process of increasing the rotational speed of the laundry dewatering tub, it passes through the resonance point of the washing machine, so if vibration or shake occurs in the laundry dewatering tub, the rotation causes uneven rotation and this is unbalanced. There may be a false detection. Also, if the mechanical accuracy is low, such as variations in the mounting position of the motor magnet or Hall element, or the surface runout accuracy of the motor rotor, it is judged that uneven rotation has occurred even during normal rotation. It may be detected as balance.

  In addition, when an imbalance is detected by a change in the duty ratio of the PWM signal while the rotation speed of the washing / dehydrating tub is maintained constant, if the imbalance is large, the rotation speed reaches a certain constant speed. Therefore, a large vibration may occur before unbalance detection is performed. For these reasons, there is a demand for a washing machine capable of more reliably and promptly detecting the imbalance of the laundry dewatering tank during dehydration.

  In particular, if an excessive amount of detergent is added during the washing process, abnormal foaming occurs during the intermediate dehydration process immediately after the washing process or during the subsequent dehydration process, and the gap between the outer tub and the washing dehydration tub is generated. If the detergent dehydration tank becomes difficult to rotate or is severely filled with detergent bubbles, the laundry dehydration tank may not turn. This is a so-called bubble restraint phenomenon. In a conventional washing machine, the rotational speed of a washing / dehydrating tub (or motor) after a predetermined time has elapsed from the start of dehydration start-up (motor start-up) is detected, and if the rotational speed does not reach a specified value, foam restraint occurs. Therefore, it is determined that the rotation speed does not increase.

  However, when performing inverter control that can generate a relatively large torque to rotationally drive the laundry dewatering tub, even if a large amount of foam is actually generated, the rotational speed of the laundry dewatering tub increases, which is normal. There may be a case where it is falsely detected. In that case, since the operation is continued in a situation where a large amount of foam is generated, that is, in a situation where the detergent concentration of the detergent water soaked in the laundry is high, the entire process is completed with the laundry not sufficiently rinsed There is a risk of it.

  In addition, if the laundry dewatering tub is rotated at high speed, such as the dewatering process, if the operation of pausing is performed, the top cover is opened, or the power is turned off, the laundry dewatering tub is rotated quickly. Need to stop. Therefore, in a conventional washing machine, a method is adopted in which the energization to the motor is cut off and the rotation of the washing and dewatering tub is forcibly stopped by a mechanical brake mechanism such as a band brake.

In the case of a structure in which the operation of the band brake is interlocked with the switching of the clutch that releases the connection between the pulsator and the washing dewatering tank, the rotor of the motor can rotate even if the washing dewatering tank is stopped by the band brake. It becomes a state. In the case of an inner rotor type motor generally used in this type of conventional washing machine, since the inertia force of the rotor is small, only the pulsator does not continue to rotate after the laundry dewatering tub stops. However, when an outer rotor type motor used in a drum-type washing machine or the like is used, the rotor diameter is large and the inertial force is remarkably large. Therefore, only the pulsator rotates for a while after the laundry dewatering tub is stopped by the band brake mechanism. It will be in the state of continuing to do.
JP-A-4-31496 JP 2002-28393 A JP 2000-325695 A

  An object of the present invention is to provide a washing machine that can prevent only the pulsator from continuing to rotate when the high-speed rotation of the laundry dewatering tank is suddenly stopped.

The present invention comprises an outer tub that is swingably disposed in an outer box that can be opened and closed by an upper lid,
A washing and dewatering tub provided rotatably around a vertical or inclined axis in the outer tub;
A stirring member rotatably disposed in the washing and dewatering tank;
An outer rotor type motor that is a drive source for rotationally driving the washing and dewatering tank and / or the stirring body;
A clutch mechanism that transmits the rotational driving force of the motor to the washing / dehydrating tub and the agitator, and that switches between rotating only the agitator and rotating the laundry dewatering tub and the agitator together. When,
A mechanical brake mechanism that stops rotation of the washing and dewatering tub when only the agitator is rotationally driven in conjunction with the switching operation of the clutch mechanism;
In the washing machine for dehydrating the laundry in the tub by rotating the laundry dewatering tub and the stirring body integrally at high speed,
Electromagnetic brake means for stopping rotation of the motor;
During the dehydration process, the mechanical dehydration tank is braked by the mechanical brake mechanism when any one of a temporary stop operation, a power-off operation, an operation of opening the upper lid, or an emergency stop due to an abnormality occurs. And an operation control means for braking the motor by the electromagnetic brake means when a predetermined time has elapsed from the start of braking,
It is characterized by having.

  Here, as an electromagnetic brake, a short circuit brake, a regenerative brake, a discharge brake, etc. can be used. The short-circuit brake is to short-circuit the motor windings, the regenerative brake is to regenerate the electromotive force of the brushless motor to the DC power supply circuit, and the discharge brake is a motor with discharge elements inserted at both ends of the input side of the inverter circuit. The electromotive force is consumed.

  In the washing machine according to the present invention, during the dehydration process, that is, when the laundry dewatering tub and the stirrer are rotated at a high speed integrally by the high-speed rotation of the motor, the user performs a temporary stop operation, The operation control means forcibly stops the rotation of the washing and dewatering tank by the mechanical brake mechanism when the operation is turned off, the upper cover is opened, or the operation needs to be stopped urgently due to the occurrence of an abnormality. Let At this time, the clutch mechanism is also switched and the agitator is separated from the washing and dewatering tank, but the operation control means forcibly stops the rotation of the motor (rotor) by the electromagnetic brake means. Although the inertia force of the rotor of the outer rotor type motor is large, the rotor is quickly stopped by the braking, and the stirrer is also stopped accordingly. Therefore, it is possible to prevent only the stirring member from continuing to rotate after the washing and dewatering tank is stopped.

  However, if a short-circuit brake is applied to the motor before the rotational speed of the motor drops after the washing dehydration tank is braked by a mechanical brake mechanism, the motor may act as a generator and an excessive current may flow through the winding of the motor. There is. Therefore, in order to prevent this, the electromagnetic brake means is first operated after the mechanical brake mechanism is actuated and the motor rotational speed actually falls below a predetermined value or after a time that can be expected to have dropped. It is good to stop the motor by operating.

  According to the washing machine of the present invention, when it becomes necessary to suddenly stop the rotation of the laundry dewatering tank during dehydration, it is possible to prevent only the stirring body from rotating after the laundry dewatering tank stops. it can.

  Hereinafter, an embodiment of a washing machine according to the present invention will be described with reference to FIGS. FIG. 1 is a right side longitudinal sectional view showing the overall configuration of the washing machine of the present embodiment.

  Inside the outer box 1 having the laundry input port 2 formed on the upper surface, a bottomed cylindrical outer tub 4 is provided with a hanging bar 5 (one in each of the front and rear in FIG. 2), and the vibration of the outer tub 4 is prevented from being transmitted to the outer box 1. The laundry input port 2 can be freely opened and closed by an upper lid 3 that can be folded in two when standing. Inside the outer tub 4, a washing / dehydrating tub 6 having a large number of water passage holes 7 on the peripheral wall is pivotally supported around a substantially vertically extending tub shaft 8 fixed to the center of the bottom surface of the bottom wall. ing. A pulsator (stirring body in the present invention) 9 for stirring the laundry is provided at the inner bottom of the laundry dewatering tub 6 so as to be rotatable around a blade shaft 10 fitted inside the tub shaft 8.

  At the bottom of the outer tub 4, a drive mechanism 11 for driving the washing and dewatering tub 6 and the pulsator 9 is provided. This drive mechanism 11 transmits a motor 12 which is a DC brushless motor provided coaxially with the tank shaft 8 and the blade shaft 10, and transmits the rotational driving force of the motor 12 only to the blade shaft 10, or the blade shaft 10 and the tank A clutch mechanism 13 that switches between transmission to both of the shafts 8 and a speed reduction mechanism 14 that reduces the rotational speed at a predetermined reduction ratio when transmitting the rotational driving force of the motor 12 only to the blade shaft 10 are included. The clutch mechanism 13 separates the tank shaft 8 and the blade shaft 10 so that only the pulsator 9 can be rotated in one direction or both directions by the operation of the torque motor 16 attached below the bottom surface of the outer tub 4, or The tank shaft 8 and the blade shaft 10 are connected so that the water tank 6 and the pulsator 9 can rotate integrally in one direction. Further, when the tank shaft 8 and the blade shaft 10 are separated from each other, the rotation of the tank shaft 8 is stopped by a band brake mechanism (corresponding to a mechanical brake mechanism in the present invention) 15.

  On the upper rear side of the outer tub 4, there is provided a water injection port 17 having a detergent container and a soft finish container for putting in detergent or the like housed therein. A water supply port 18 connected to an external water tap or the like via a hose is provided on the rear upper surface of the outer box 1, and a water supply pipe 19 connected to the water supply port 18 is connected to the water injection port portion 17 via a water supply valve 20. It is connected. When the water supply valve 20 is opened, tap water supplied from the water tap flows into the water inlet 17 through the water supply pipe 19, and water is discharged from the water inlet 17 toward the lower outer tank 4. By storing the detergent in a predetermined place in the detergent container in advance, the detergent can be mixed into the water discharged into the outer tub 4, and thus the detergent can be automatically introduced. In this washing machine, a bath water pump is provided as another means for supplying water into the washing and dewatering tank 6, but the description thereof is omitted here.

  A drainage port 21 is provided at the bottom of the outer tub 4, and a drainage pipe 22 connected to the drainage port 21 is opened and closed by a drainage valve 23. The opening / closing operation of the drain valve 23 is interlocked with the operation of the clutch mechanism 13 (that is, the operation of the torque motor 16), and the pulsator 9 is separated from the washing / dehydrating tub 6 and can be rotated independently (the washing / dehydrating tub 6). The drain valve 23 is closed when the rotation is restricted by the band brake mechanism 15, and the drain valve 23 is opened when the pulsator 9 and the washing and dewatering tub 6 can rotate together.

  A circulation water channel 26 having openings at the upper and lower ends is formed on the inner wall surface of the laundry dewatering tub 6, and a water passage 27 is provided on the bottom wall surface of the laundry dewatering tub 6 below the pulsator 9. When the pulsator 9 is rotationally driven in a state where an appropriate amount of water is stored in the outer tub 4, the outer wall of the washing / dehydrating tub 6 is separated from the bottom wall of the washing / dehydrating tub 6 through the water outlet 27 by the pumping action of the back blade provided on the back surface of the pulsator 9. Water between the bottom wall of the tank 4 is sucked into the washing / dehydrating tank 6 and fed into the lower end opening of the circulation water channel 26. The water ascends in the circulation water channel 26 and is discharged into the washing and dewatering tub 6 through a lint filter 28 provided on the upper portion thereof. As a result, lint and dust floating in the water are collected.

  In addition, a vibration detection lever 29 (corresponding to vibration detection means in the present invention) 29 connected to a vibration detection switch 47 described later is installed in the gap between the outer tub 4 and the outer box 1, and the outer tub 4 becomes abnormal. This rocking can be mechanically detected when rocking greatly. Further, although not shown, an air trap is formed at the bottom of the outer tub 4 and the other end of the air hose connected to the air trap is connected to a water level sensor 46 described later. Thereby, the water level of the water stored in the washing and dewatering tank 6 can be detected. An operation panel 30 is provided on the front side of the upper surface of the outer box 1, and a circuit unit 31 including an electric board on which various electric components are mounted is disposed below the operation panel 30.

  The configuration of the drive mechanism 11 will be described in detail with reference to FIG. An upper bearing case 51 that opens downward is integrally provided on a metal motor mounting base 50 that is attached to the bottom of the outer tub 4, and a lower bearing case 52 that opens upward is provided below the upper bearing case 51. It is fixed to the mounting base 50. An upper bearing 53 and an oil seal 54 are provided in the upper part of the upper bearing case 51, and the tank shaft 8 is instructed to be watertight and rotatable through these. A gear case composed of an upper gear case 55 and a lower gear case 56 is fixed to the outside of the lower end of the tank shaft 8, and a gear mechanism 57 that functions as the speed reduction mechanism is accommodated in the gear case. ing. The gear mechanism 57 is for reducing the driving force applied through the driving shaft 58 having the rotor 122 of the motor 12 fixed to the lower end thereof at a predetermined reduction ratio and transmitting the driving force to the blade shaft 10. A lower bearing 59 is provided in the lower portion of the lower bearing case 52, through which the gear case is instructed to be rotatable. That is, the tank shaft 8, the upper gear case 55, and the lower gear case 56 are integrally supported by the upper bearing 53 and the lower bearing 59 so as to be rotatable.

  The motor 12 is a so-called outer rotor type motor, and is fixed to the lower part of the stator 121, the rotor 122 disposed on the outer peripheral side so as to surround the stator 121, and the lower bearing case 52, and holds the stator 121 and the clutch mechanism 13. And a stator fixing base 123 containing the. The rotor 122 to which the drive shaft 58 is fixed has a bottomed flat cylindrical shape, and a plurality of magnets 124 are arranged along the rotation direction so as to face the stator 121 inside the peripheral wall. Further, at a plurality of locations on the back side of the top surface of the stator fixing base 123 (only one location appears in FIG. 2), a Hall element that detects the rotational position of the rotor 122 by detecting the magnetic force of the magnet 124 of the rotor 122. 125 is attached.

The clutch mechanism 13 is provided at the lower end of the drive shaft 58, and has an outer diameter that is substantially the same as the outer diameter of the lower end of the lower gear case 56, and from the clutch wheel 60 to the lower end of the lower gear case 56. A clutch spring 61 wound around the outer periphery of the clutch spring 61, a hook wheel 62 provided around the clutch spring 61 and engaged with the lower end of the clutch spring 61, and an engagement / disengagement of the pinion wheel 62. A claw portion 63 includes a clutch lever 64 provided at the tip. The clutch lever 64 is rotatably supported around a vertically extending clutch shaft 65, and is urged by a coil spring 66 in a direction in which the claw portion 63 is engaged with the claw wheel 62.

The band brake mechanism 15 includes a brake band 67 wound around the outer peripheral surface of the upper gear case 55 that is a brake drum surface, and a brake lever 68 for tightening or loosening the brake band 67. The brake lever 68 is rotatably supported on the clutch shaft 65 at a position above the clutch lever 64 in the same manner as the clutch lever 64. The brake lever 68 and the clutch lever 64 are connected to the torque motor 16 by a connecting member or a wire (not shown), and operate in conjunction with the torque motor 16.

  When the torque motor 16 that is the driving source is not energized, the claw portion 63 of the clutch lever 64 is engaged with the claw wheel 62. For this reason, the lower end side of the clutch spring 61 is displaced in the expanding direction, and the clutch wheel 60 and the lower end portion of the lower gear case 56 are not coupled. Therefore, the rotational driving force of the motor 12 is not transmitted to the tank shaft 8 but is transmitted only to the blade shaft 10. At this time, the brake band 67 is fastened by the brake lever 68, and the upper gear case 55, that is, the washing and dewatering tub 6 is fixed by the braking force of the band brake mechanism 15.

  In the above state, since the rotational driving force of the motor 12 is transmitted from the driving shaft 58 to the blade shaft 10 via the gear mechanism 57, that is, the speed reduction mechanism 14, the washing / dehydrating tub 6 does not rotate and only the pulsator 9 rotates. Rather, it is rotationally driven in the same direction at a rotational speed reduced by a predetermined reduction ratio. Such rotational drive is used in the case of washing operation or rinsing operation in which water is stored in the washing and dewatering tank 6.

  When the torque motor 16 is energized, the torque motor 16 operates to wind up a wire (not shown), whereby the clutch lever 64 rotates in a direction against the biasing direction by the coil spring 66, and the claw portion 63 is moved. Detach from claw wheel 62. As a result, the displacement of the clutch spring 61 is released, and the clutch wheel 60 and the lower end of the lower gear case 56 are coupled by tightening the clutch spring 61. Accordingly, the rotational driving force of the motor 12 is directly transmitted to both the tank shaft 8 and the blade shaft 10. When the clutch lever 64 is rotated, the brake lever 68 is also rotated through a connecting member (not shown), and the brake band 67 is loosened. Thereby, the braking force by the band brake mechanism 15 is released, the fixation of the washing and dewatering tub 6 is released, and a state where the washing and dewatering tub 6 can freely rotate is set.

  In the above state, the rotational driving force of the motor 12 is transmitted from the drive shaft 58 to the lower gear case 56, the upper gear case 55, and the tank shaft 8, and is also transmitted directly from the upper gear case 55 to the blade shaft 10 via the gear mechanism 57. The laundry dewatering tub 6 and the pulsator 9 are integrally driven to rotate in the same rotational speed and rotational direction as the motor 12. Such rotational drive is used during a dehydration process or the like.

  Next, the configuration of the electric system of the washing machine of this embodiment will be described with reference to FIG. FIG. 3 is an electric system configuration diagram of a main part of the washing machine of the present embodiment.

  At the center of control is a main control unit (corresponding to unbalance detection means, operation control means, load amount estimation means, determination means in the present invention) 40 that includes a CPU, RAM, ROM, timer, and the like. ing. The main control unit 40 receives a key signal from an operation unit 43 having a plurality of operation keys such as a course selection key and a start key, and a lid opening / closing signal linked to opening / closing of the upper lid from the upper lid switch 45, and a water level sensor 46 to the outer tub. A vibration detection signal generated when a water level detection signal corresponding to the water level of water stored inside 4 detects a large swing of the outer tub 4 from the vibration detection switch 47 is input. The main control unit 40 controls the opening / closing operation of the water supply valve 20, the operation of the bath water pump 48, and the operation of the torque motor 16 via the load driving unit 41. As described above, the torque motor 16 achieves the connecting / disconnecting operation of the clutch mechanism 13, the braking / releasing of the washing / dehydrating tub 6 by the band brake mechanism 15, and the opening / closing operation of the drain valve 23. Furthermore, the main control unit 40 causes the display unit 44 to display the key input acceptance state of the operation unit 43 and the progress of washing, and a buzzer as necessary to alert the user (the present invention). The abnormality notifying means) 49 is sounded.

  In addition, an inverter circuit 70 is provided to drive the motor 12. The inverter circuit 70 includes an AC / DC conversion circuit 71 that converts AC power into DC power, a switching circuit 72 that includes a plurality of switching elements that switch a DC current to supply a three-phase AC current to the motor 12, and a PWM signal that will be described later. A motor control unit (including a drive unit 73 that drives the power and supplies the switching device to each switching element, and outputs a PWM signal for turning on / off each switching element of the switching circuit 72 while communicating with the main control unit 40) 74 corresponding to the drive control means and electromagnetic brake means in the present invention) 74, a rotation detector (corresponding to the speed detecting means in the present invention) 75 including the Hall element 125 described above and generating a pulse signal synchronized with the rotation of the motor 12, Is provided. The motor control unit 74 controls the drive power applied to the motor 12 by adjusting the ratio of on (signal level “H”) time within one cycle of ON / OFF of each pulse of the PWM signal, that is, the duty ratio. Therefore, if the duty ratio is increased (that is, close to 100%), the torque of the motor 12 is increased, and if the duty ratio is decreased (that is, close to 0%), the torque of the motor 12 is decreased.

  FIG. 4 is a plan view showing the operation panel 30, where the upper one is positioned on the left side, and the lower one is positioned on the right side. The operation panel 30 includes a power key 301, a start key 302, a course selection key 303 for a washing course, a manual course setting key 304, a water amount setting key 305, a bath water use setting key 306, a reservation setting key 307, and the like as operation keys. Is provided. The course display group 308 including nine LEDs for displaying the contents of the washing course selected by the course selection key 303 and the operation time and the number of times of each process set by the manual course setting key 304 are displayed. A set content indicator group 309 composed of 16 LEDs, a water amount indicator group 310 composed of 5 LEDs for displaying the amount of water selected by the water amount setting key 305, a remaining operation time and a reservation setting key 307. A numerical display 311 for displaying the reservation time and the like is provided.

  When the user presses the power key 301 in the power-off state, all the indicators (LEDs) on the operation panel 30 are lit in order so as to move from the left end (that is, the water amount indicator group 310) to the right. Go. Since all the indicators are lit once, the user can recognize this if the indicators do not illuminate due to failure or disconnection of the indicators. In particular, in the case where a display device that notifies an abnormal state is provided, the abnormal state cannot be notified unless the display device is turned on due to a failure. However, the presence or absence of a failure can be confirmed by checking the lighting when the power is turned on. It should be noted that after all the indicators are lit up, only a predetermined initial indicator is lit up.

  Next, the control operation in the dehydration process, which is one of the features of the washing machine of the present embodiment, will be described with reference to FIGS. 5 and 6 are flowcharts of the eccentricity (unbalance) detection process at the time of the dewatering process, and FIG. 7 is a schematic diagram for explaining the change state of the rotational speed of the laundry dewatering tank and the duty ratio of the PWM signal at the initial stage of the dewatering process. is there.

It is assumed that the drain valve 23 is opened at the start of the dehydration process, and the water in the outer tub 4 is discharged out of the machine. When the dehydration process is started in this state, the main control unit 40 first turns on the torque motor 16 and switches the clutch mechanism 13 so that the laundry dewatering tub 6 and the pulsator 9 can rotate integrally. Then, the motor 12 is energized to start the motor 12 (step S1). As a result, the washing and dewatering tank 6 and the pulsator 9 start to rotate together. At the time of starting, the main control unit 40 acquires the duty ratio of the PWM signal from the motor control unit 74 and stores it as the initial duty ratio D ₀ (step S2). Then, the main control unit 40 determines a load amount that is the weight of the water-containing laundry contained in the laundry dewatering tub 6 according to the initial duty ratio D ₀ (step S3). The larger the load amount, the larger the duty ratio because a larger starting torque is required when starting up the rotation of the washing and dewatering tub 6. Therefore, it can be determined which of the plurality of stages the load amount is based on which of the predetermined ranges the duty ratio value falls.

  Next, it is determined whether or not the load amount obtained as a determination result is small, that is, whether or not the load amount is smaller than a predetermined load amount (step S4). When the load amount is small, the duty ratio difference described later is relatively small even if the laundry is displaced. On the other hand, when the mechanical accuracy in manufacturing such as the axis deviation or the axis inclination of the motor 12 is low, a duty ratio difference described later appears relatively large even if there is no eccentricity due to the deviation of the laundry. Therefore, when trying to widen the allowable range of mechanical accuracy of the motor used, etc., a distinction is made between the duty ratio difference due to the deviation of the laundry when the load is small and the duty ratio difference due to variations in mechanical accuracy. This makes it difficult to detect eccentricity substantially accurately. Therefore, it is often useless to attempt eccentricity detection and correction as will be described later. Therefore, the rotational speed of the washing dewatering tub 6 is increased to a high speed dehydration rotational speed (for example, about 600 to 900 rpm) without performing the eccentricity detection processing. The motor 12 is driven so as to start up, and dehydration is performed while maintaining the rotation speed (step S22).

  Note that the detection of the swinging of the outer tub 4 by the vibration detection lever 29 and the vibration detection switch 47 is always performed. Therefore, if the outer tub 4 vibrates greatly until and after the rotational speed of the washing dewatering tub 6 reaches the high speed dewatering rotational speed, the vibration detection lever 29 is pushed by the outer tub 4 and the vibration by the vibration detection switch 47 is vibrated. A detection signal is input to the main control unit 40. Thereby, the main control unit 40 recognizes the abnormal vibration, for example, stops the energization of the motor 12 and temporarily stops the operation.

  If it is determined in step S4 that the load amount is not small, that is, there is a certain load or more, the main control unit 40 determines the eccentricity detection threshold U according to the load amount (step S6). This can be obtained by reading necessary data from a table previously determined at the time of factory shipment. When the rotational speed of the washing / dehydrating tub 6 reaches the predetermined speed P1, the speed is maintained for a while (step S7). For example, as shown in FIG. 7B, the predetermined speed P1 is set to 120 rpm, which is lower than the resonance point (about 200 rpm) of the washing machine. The main control unit 40 determines whether or not an eccentricity detection process, which will be described later, has been continuously executed four times (step S8). If the eccentricity detection process has not been continuously executed four times, the main control unit 40 proceeds to step S11 and starts the eccentricity detection process. That is, in order to increase the rotation speed of the washing and dewatering tub 6 from 120 rpm to 240 rpm, acceleration control of the motor 12 is performed at a target rotation speed of 240 rpm. Since acceleration requires a larger torque than before, the duty ratio of the PWM signal output from the motor control unit 74 becomes larger than before.

The main control unit 40 waits until 5 seconds after the start of acceleration has elapsed (step S12), the determining which the reference value D _r to obtain the duty ratio of the PWM signal at the time when 5 seconds have elapsed (step S13). Wait until then one second has elapsed (step S14), and acquires the duty ratio D _n after one second has elapsed (step S15). Here, n is a value that is incremented sequentially from n = 1 every time step S15 is executed. Therefore, when the first time step S15 is performed is obtained duty ratio D _1. Next, calculate the difference [Delta] D _n between the reference value D _r obtained at duty ratio D _n and the step S 13 obtained in step S15 (step S16), and the difference D _n by integrating from n = 1 in the order A value ΣΔD _n is obtained to determine whether ΣΔD _n is equal to or smaller than the eccentricity detection threshold U (step S17).

If the duty ratio difference integrated value ShigumaderutaD _n is less eccentric detection threshold U, it is judged whether or not the 10 seconds from the reference value D _r decision point in step S13 has elapsed (step S20), it has not elapsed 10 seconds Return to step S14. Therefore, if you follow a determination that the duty ratio difference integrated value ShigumaderutaD _n or less eccentric detection threshold U in step S17, by repeating the steps S14, S15, S16, S17, S20, the duty ratio D _n every second acquired by the duty ratio duty ratio difference integrated value ShigumaderutaD _n reflecting the D _n is subjected to the determination. As shown in FIG. 7A, when the eccentricity is small and the duty ratio converges substantially constant in a relatively short time, the step without the duty ratio difference integrated value ΣΔD _n exceeding the eccentricity detection threshold U as described above. It is determined YES in S20, and the eccentricity detection process ends (step S21).

In contrast, since the slide into similarly also increased duty ratio difference integrated value ShigumaderutaD _n if the eccentricity is large duty ratio as shown in FIG. 7 (a) slide into continuously increasing, the reference value D _r determined Prior to the elapse of 10 seconds from the time, the duty ratio difference integrated value ΣΔD _n exceeds the eccentricity detection threshold value U. In that case, the process proceeds from step S17 to S18, where the washing and dewatering tub 6 is temporarily stopped and a rinsing operation for correcting eccentricity is executed. That is, the clutch mechanism 13 is switched and the drain valve 23 is closed, and the laundry dewatering tank 6 is braked by the band brake mechanism 15 so that only the pulsator 9 can rotate, and then water is supplied into the outer tank 4. . When appropriate water is stored in the outer tub 4, the pulsator 9 is rotated by driving the motor 12 in the left-right direction so that the laundry is stirred in water. When the predetermined rinsing time is over (YES in step S19), the drain valve 23 is opened to discharge the water in the outer tub 4, and the process returns to step S1 to execute the dehydration process again. If the deviation of the laundry in the washing and dewatering tub 6 is eliminated by the rinsing operation, the duty ratio difference integrated value ΣΔD _n does not exceed the eccentricity detection threshold value U in the next eccentricity detection process, and YES in step S20. Thus, the eccentricity detection process ends.

  Even when it is determined in step S4 that the load amount is not small, since the mechanical detection of the swinging of the outer tub 4 by the vibration detection lever 29 and the vibration detection switch 47 is in the execution state, acceleration is performed, for example, when detecting the eccentricity. If the outer tub 4 vibrates greatly when the control is performed and a vibration detection signal is output by the vibration detection switch 47, the eccentricity correction rinsing operation is executed in the same manner as when NO is determined in step S17.

  The eccentricity detection process and the eccentricity correction rinsing operation as described above are repeated up to four times. However, if the eccentricity is still not resolved, the process proceeds from step S8 to S9, and the main control unit 40 performs the same operation in five consecutive operation cycles. It is determined whether or not the processing, that is, the eccentricity detection processing and the eccentricity correction rinsing operation are repeated four times. For this purpose, the main control unit 40 counts the number of consecutive operation cycles including a dehydration process in which the eccentricity detection process and the eccentricity correction rinsing operation are repeated four times, and stores the counting result in, for example, a nonvolatile memory. deep. If the same process is not executed in five consecutive operation cycles, the process proceeds to step S21 to end the eccentricity detection process. Therefore, even if the eccentricity correction rinse operation is repeated four times, YES is determined in steps S17 and S20. If there is an eccentricity that is not performed, no further eccentricity detection processing is performed, and the process proceeds to a dehydrating operation by high-speed dehydrating rotation. Thereby, even when the eccentricity does not become small, the dehydration operation time is prevented from being prolonged abnormally. Even in such a case, since the vibration of the mechanical outer tub 4 is detected by the vibration detection switch 47, abnormal vibration and abnormal noise due to large eccentricity can be prevented.

  If it is determined in step S9 that the same process has been executed in five consecutive operation cycles, it is not determined that the laundry is not well balanced and the eccentricity is large. Specifically, it is considered that the mechanical accuracy of the motor 12 or the like as described above is so low that it falls outside the allowable range, or that there is a high possibility that a malfunction such as a failure has occurred. Therefore, the buzzer 49 is sounded and an abnormality is notified on the display unit 44 (step S10), and the operation is stopped (step S23). As a result, the user can take appropriate measures such as recognizing an abnormality and contacting a service representative.

  As described above, in the washing machine according to the present embodiment, the eccentricity of the laundry dewatering tub 6 caused by the deviation of the laundry around the rotation axis is determined based on the duty ratio of the PWM signal for inverter-controlling the motor 12. Therefore, the eccentricity can be detected with high accuracy and quickly (at a rotational speed considerably lower than the high-speed dehydrating rotational speed).

  Next, the bubble constraint detection process executed in parallel with the above-described eccentricity detection process during the dehydration process will be described with reference to the flowchart of FIG.

When the dehydration process is started, the main control unit 40 turns on the torque motor 16 to switch the clutch mechanism 13 so that the washing dewatering tub 6 and the pulsator 9 can rotate integrally, and then the motor 12 is energized. To start the motor 12 (step S32). As a result, the washing and dewatering tank 6 and the pulsator 9 start to rotate together. At the time of starting, the main control unit 40 acquires the duty ratio of the PWM signal from the motor control unit 74 and stores it as the initial duty ratio D ₀ (step S33). The main control unit 40 determines load is weight of the laundry that moisture contained in the laundry drying tub 6 in response to the initial duty ratio D ₀ (step S34). The processes in steps S32 to S34 are the same as those in steps S1 to S3 described above. When the load amount is determined, the main control unit 40 determines the first and second threshold values Q ₁ and Q ₂ according to the load amount (step S35). This can also be obtained by reading necessary data from a table previously determined at the time of factory shipment. Since the required torque increases when the load amount is large, the threshold values Q ₁ and Q ₂ are generally increased as the load amount increases.

Then, the target rotational speed is set to 240 rpm, for example, and the low speed dewatering is executed while increasing the rotational speed of the washing dewatering tub 6, that is, the motor 12 (step S36). Then, until the rotational speed reaches the target rotational speed, obtains the duty ratio Da of the repeating PWM signal (step S37), whether the duty ratio Da is smaller than the first threshold value Q ₁ as defined in previously not Is determined (step S38). When the concentration of the detergent water contained in the laundry is high at the start of dehydration, the detergent water discharged from the laundry is rotated between the bottom of the laundry dewatering tank 6 and the bottom of the outer tank 4 by rotating the laundry dewatering tank 6. When the mixture is vigorously stirred, abnormal foaming occurs, filling the gap between the outer tub 4 and the laundry dewatering tub 6 and causing a load on the rotation of the laundry dewatering tub 6. Therefore, a larger torque is required to increase the rotational speed of the motor 12 to the same rotational speed, and as a result, the duty ratio of the PWM signal is increased.

Therefore, when the duty ratio Da is the first threshold Q ₁ or more is judged that the form of bubbles constrained state, executes the rinsing operation for defoaming proceeds to step S50. Basically, this is the same as the above-described rinsing operation for correcting eccentricity, but it is desirable to increase the amount of water supplied into the outer tub 4 for the purpose of eliminating bubbles. If the predetermined rinsing operation time is over (YES in step S51), the process returns to step S32 to retry from the start of the dehydration process. Since the concentration of the detergent water contained in the laundry is lowered by the rinsing operation, bubbles are less likely to be generated the next time the dehydration process is started.

If the duty ratio Da reaches the target rotational speed without the first threshold value Q ₁ or more (YES at step S39), then washing and dewatering tub 6 the target rotational speed as that for example 850rpm fast dehydration speed, i.e. Performs high-speed dewatering while increasing the rotational speed of the motor 12 (step S40). Then, until the rotational speed reaches the target rotational speed, it obtains the duty ratio Db of repeating PWM signal (step S41), whether the duty ratio Db is smaller than the second threshold value Q ₂ to which defined previously not Is determined (step S42). At this time, since the target rotational speed is high, the duty ratio of the PWM signal is larger than that during the low-speed dehydration even when the bubble is not constrained, and accordingly, the second threshold value Q ₂ is larger than the first threshold value Q _1. It is good to set the value.

When the duty ratio Db is the second threshold value Q ₂ or more is judged that the form of bubbles constrained state, it executes the rinsing operation for defoaming proceeds to step S50 described above. On the other hand, if the duty ratio Db has reached the target rotation speed without a second threshold value Q ₂ or more (YES at step S43), the rotation speed control of the motor 12 so as to maintain the high-speed dewatering rotation speed ( Step S44). Get the duty ratio D ₁ of the PWM signal is stored after starting the rotational speed constant control (step S45), then a specified time (e.g., several seconds to 30 seconds) Wait until elapses (step S46), again PWM It acquires the duty ratio D ₂ signal (step S47).

Generally, when water is drained from the laundry due to the progress of dehydration, the weight is reduced, and the load on the motor 12 is reduced, so that the duty ratio of the PWM signal is reduced. Therefore, if the duty ratio D ₂ after the lapse of the specified time is greater than D _1, bubbles are gradually generated from the detergent water discharged from the laundry after the high-speed dehydration transition. It can be determined that the bubble has become confined by filling. Therefore, erasing bubbles proceeds to the duty ratio D ₂ is equal to or a D ₁ or less (step S48), the step S50 it is determined that if D ₂ is not D ₁ less a foam constrained state Perform a rinsing operation for. Thereby, even when foam restraint occurs as the dehydration progresses without being in the foam restraint state at the beginning of the dehydration process, the dehydration can be interrupted and the process can be shifted to the rinse.

D ₂ In step S48, it is determined whether the elapse of a predetermined dehydration time when it is D ₁ or less (step S49), when not reached the flow returns to step S47. Therefore, the duty ratio D ₂ is repeatedly acquired until the dehydration operation is completed, and the presence / absence of bubble restraint is determined by comparing D ₂ with D ₁ . When a predetermined dehydration time has elapsed, the dehydration process is terminated and the process proceeds to the next process.

  As described above, in the washing machine according to the present embodiment, bubbles are generated in the dehydration process as the detergent water discharged from the laundry is stirred from the time when the rotational speed of the laundry dewatering tub 6 is started up to the time when the high speed dewatering rotation is started. It is possible to detect the restraint state with high accuracy and shift to the rinsing operation when the state is the bubble restraint state. As a result, the entire washing operation is not completed in a state where detergent water having a high detergent concentration remains in the laundry, and good washing can be performed.

  Next, braking control during high-speed rotation of the washing and dewatering tub 6 as another feature of the washing machine of this embodiment will be described with reference to the flowchart of FIG. As described above, this washing machine uses an outer rotor type motor as the motor 12, and the inertia force of the rotor 122 is larger than that of the inner rotor type motor. On the other hand, when the laundry dewatering tub 6 needs to be stopped suddenly when the laundry dewatering tub 6 is rotating at high speed integrally with the pulsator 9 at the time of the dewatering process as described above, specifically, the start key 302 is used for temporary stop. Is pressed, when the power key 301 is pressed to turn off the power, when the user opens the top lid 3 for the purpose of looking into the inside of the washing and dewatering tub 6, etc. When it is necessary to stop the operation due to an abnormality, the band brake mechanism 15 is operated to forcibly stop the rotation of the washing / dehydrating tub 6. At the same time, the washing / dehydrating tub 6 and the pulsator 9 are Therefore, even if the washing and dewatering tub 6 is stopped, the pulsator 9 can be rotated, and only the pulsator 9 is washed by the driving force of the rotor 122 that rotates by the inertial force. It will continue to rotate in the water tank 6. Therefore, in order to avoid such a state, in the washing machine of this embodiment, the motor 12 is forcibly stopped using a short-circuit brake, which is a kind of electromagnetic brake, when the laundry dewatering tank 6 is suddenly stopped. ing.

  That is, after the dehydration process is started and the motor 12 is started (step S62), the main control unit 40 instructs to stop by operating the start key 302, to instruct power off by operating the power key 301, and the upper lid switch 45. It is determined whether or not there is an emergency stop command due to the detection of the opening operation of the upper lid 3 by the occurrence of an abnormality or the like (step S63), and if it is not necessary to stop the washing / dehydrating tank 6 suddenly, the dehydration operation is continued. To do.

  On the other hand, when it is necessary to stop the washing / dehydrating tub 6 suddenly, for example, when a stop instruction is given, the main control unit 40 operates the band brake mechanism 15 by the torque motor 16 to brake the rotation of the washing / dehydrating tub 6. Is started (step S64). At substantially the same time, the clutch mechanism 13 releases the connection between the washing and dewatering tub 6 and the pulsator 9. The rotation speed of the washing and dewatering tub 6 is lowered by the operation of the band brake mechanism 15. Then, the main control unit 40 determines whether or not the rotation speed of the motor 12 is equal to or less than a predetermined threshold based on the detection signal from the rotation detector 75 (step S65). The short circuit brake is activated (step S66). Specifically, for example, the windings are short-circuited by simultaneously turning on the switching elements of the three-phase lower arms of the switching circuit 72. As a result, a braking force acts on the rotating rotor 122.

  If the short-circuit brake is operated in a state where the rotational speed of the motor 12 is high, the current flowing through the winding of the motor 12 becomes abnormally large, and in the worst case, the winding may be burned out. The current flowing through the windings can be suppressed by delaying the operation of the short-circuit brake until the determination becomes YES.

  Almost simultaneously with the operation of the short-circuit brake, the main control unit 40 displays on the display unit 44 that the short-circuit brake is in operation (step S67). This is because a loud sound is generated when the short-circuit brake is operated, so that the user can recognize that this is not abnormal. The rotation of the rotor 122 of the motor 12 is quickly stopped by the operation of the short-circuit brake, and accordingly, the rotation of the pulsator 9 is also stopped. If the motor 12 is stopped (YES in step S68), the display during the operation of the short-circuit brake is canceled (step S67), and depending on the type of operation that triggered the stop (step S70), for example, the power supply Transition to an appropriate state such as blocking (step S72) or transition to a pause state (step S71).

  By the control as described above, it is possible to avoid that only the pulsator 9 continues to rotate when the washing and dewatering tub 6 is stopped. In the above description, the short-circuit brake is operated regardless of the rotation state of the washing / dehydrating tub 6. However, the short-circuit brake may be operated after the rotation of the washing / dehydrating tub 6 is completely stopped.

  In addition, instead of detecting that the rotational speed has fallen below the threshold in step S65 and operating the short-circuit brake, it is considered that the rotational speed has sufficiently decreased when a certain time has elapsed since the start of the band brake operation. The short-circuit brake may be activated. However, since the braking force of the band brake mechanism 15 differs depending on the degree of wear of the band brake, the number of operations increases and the wear of the band brake progresses until the rotational speed drops to a predetermined speed from the start of the band brake operation. The required time becomes longer. Therefore, for example, the number of times of operation from the use start time of the washing machine (or the replacement time of the band brake) may be counted, and the reference value for determining the time from the start of operation of the band brake may be changed according to the value.

  Further, this washing machine does not have an upper lid locking mechanism that locks the upper lid 3 in a closed state. However, in the case of a washing machine provided with an upper lid locking mechanism, the upper lid locking mechanism is activated at the start of the dehydration process. The upper lid 3 should not be opened immediately, and when the washing / dehydrating tank 6 is suddenly stopped, the short-circuit brake is activated and the motor 12 is stopped, and then the upper lid lock is released so that the upper lid 3 is freely opened. Moreover, although the short-circuit brake is used in the above embodiment, other types of electromagnetic brakes such as a regenerative brake and a discharge brake may be used.

  Further, the above-described embodiment is merely an example, and it is obvious that even if changes, modifications, and additions are appropriately made within the scope of the present invention, they are included in the scope of the claims of the present application. For example, the above embodiment is a vertical type washing machine that rotates a washing / dehydrating tub around a vertical rotation axis, but the rotation axis may be inclined, and the drum type washing machine has a substantially horizontal rotation axis. There may be.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side sectional view showing an overall configuration of a washing machine according to an embodiment of the present invention. The block diagram of the drive mechanism in the washing machine of a present Example. The electric system block diagram of the principal part of the washing machine of a present Example. The top view which shows the operation panel of the washing machine of a present Example. The flowchart of the eccentricity detection process at the time of a dehydration process with the washing machine of a present Example. The flowchart of the eccentricity detection process at the time of a dehydration process with the washing machine of a present Example. Schematic for demonstrating the change state of the rotational speed of a washing | cleaning dehydration tank and the duty ratio of a PWM signal in the washing machine of a present Example in the dehydration process initial stage. The flowchart of the bubble restraint detection process in a dehydration process with the washing machine of a present Example. The flowchart which shows the braking control at the time of the high-speed rotation of a washing dewatering tank with the washing machine of a present Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Outer box 2 ... Laundry insertion port 3 ... Upper lid 4 ... Outer tub 5 ... Hanging rod 6 ... Laundry dehydration tub 7 ... Water passage hole 8 ... Tank shaft 9 ... Pulsator 10 ... Blade shaft 11 ... Drive mechanism 12 ... Motor 121 ... Stator 122 ... Rotor 123 ... Stator fixing base 124 ... Magnet 125 ... Hall element 13 ... Clutch mechanism 14 ... Deceleration mechanism 15 ... Band brake mechanism 16 ... Torque motor 17 ... Water injection port 18 ... Water supply port 19 ... Water supply pipe 20 ... Water supply Valve 21 ... Drain port 22 ... Drain pipe 23 ... Drain valve 26 ... Circulating water channel 27 ... Water vent 28 ... Lint filter 29 ... Vibration detection lever 30 ... Operation panel 301 ... Power key 302 ... Start key 303 ... Course selection key 304 ... Manual course setting key 305 ... Water volume setting key 306 ... Bath water use setting key 307 ... Reservation setting key 308 ... Course indicator group 309 ... Setting content indicator group 310 ... Water Display group 311 ... Numerical display 31 ... Circuit unit 40 ... Main control unit 41 ... Load drive unit 43 ... Operation unit 44 ... Display unit 45 ... Top cover switch 46 ... Water level sensor 47 ... Vibration detection switch 48 ... Bath water pump 49 ... Buzzer 50 ... Motor mount 51 ... Upper bearing case 52 ... Lower bearing case 53 ... Upper bearing 54 ... Oil seal 55 ... Upper gear case 56 ... Lower gear case 57 ... Gear mechanism 58 ... Drive shaft 59 ... Lower bearing 60 ... Clutch wheel 61 ... Clutch spring 62 ... Claw wheel 63 ... Claw part 64 ... Clutch lever 65 ... Clutch shaft 66 ... Coil spring 67 ... Brake band 68 ... Brake lever 70 ... Inverter circuit 71 ... AC / DC converter circuit 72 ... Switching circuit 73 ... Drive part 74 ... Motor control unit 75 ... Rotation detector

Claims (1)

An outer tub that is swingably disposed in an outer box that can be opened and closed by an upper lid;
A washing and dewatering tub provided rotatably around a vertical or inclined axis in the outer tub;
A stirring member rotatably disposed in the washing and dewatering tank;
An outer rotor type motor that is a drive source for rotationally driving the washing and dewatering tank and / or the stirring body;
A clutch mechanism that transmits the rotational driving force of the motor to the washing / dehydrating tub and the agitator, and that switches between rotating only the agitator and rotating the laundry dewatering tub and the agitator together. When,
A mechanical brake mechanism that stops rotation of the washing and dewatering tub when only the agitator is rotationally driven in conjunction with the switching operation of the clutch mechanism;
In the washing machine for dehydrating the laundry in the tub by rotating the laundry dewatering tub and the stirring body integrally at high speed,
Electromagnetic brake means for stopping rotation of the motor;
During the dehydration process, the mechanical dehydration tank is braked by the mechanical brake mechanism when any one of a temporary stop operation, a power-off operation, an operation of opening the upper lid, or an emergency stop due to an abnormality occurs. And an operation control means for braking the motor by the electromagnetic brake means when a predetermined time has elapsed from the start of braking,
A washing machine comprising: