JP2000140481A - Drum type washing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect a small load amount. SOLUTION: From the state of stopping a drum, an application voltage to a motor for rotationally driving the drum is gradually raised by gradually increasing the duty factor of PWM control signals (S1-S4) and the duty factor at the time of reaching 45 rpm which is a rotation speed immediately after the drum starts rapid rotation is stored as A1 (S5). In the case that the load amount is small, since large torque is required for lifting a baffle upwards against gravity acting on laundry mounted on the baffle inside the drum, the application voltage immediately before starting the rotation of the drum depends on the load amount. Thus, by discriminating the A1, the load amount is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum type washing machine, and more particularly, to a load detecting device for detecting a load of laundry before starting a spin-drying operation. The washing machine according to the present invention includes not only a washing machine using water but also a washing machine for dry cleaning using a washing solvent.

[0002]

2. Description of the Related Art In a drum-type washing machine, when laundry is unbalanced around a rotation axis during a spin-drying operation, a drum and an outer tub vibrate greatly, and abnormal noise is generated. Therefore, in a general drum type washing machine, a weight is attached around an outer tub in which a drum is installed in order to suppress abnormal vibration. For this reason, the drum type washing machine is very heavy, the installation place is limited, and it is difficult to move and transport.

[0003] In order to cope with such a problem, before the spinning is started (that is, before the rotation speed of the drum is increased to a rotation speed at which the spinning is substantially performed), the laundry is put on the inner periphery of the drum. Several balance adjustment methods have been proposed to reduce the eccentric load by properly dispersing. For example, in Japanese Patent Application No. 9-249917 or the like, the present applicant forms a pocket-shaped variable weight balancer capable of temporarily holding water in one of a plurality of baffles provided on the inner peripheral wall of a drum,
When an eccentric load due to the uneven distribution of the laundry exists near the position facing the balancer on the inner periphery of the drum, an appropriate amount of water corresponding to the magnitude (eccentric amount) of the eccentric load is injected into the balancer. Thus, a centrifugal dehydrator having a novel configuration that adjusts the balance of the entire drum has been proposed.

[0004]

In such a drum type washing machine, if the detection of the magnitude of the eccentric load is not accurate, the amount of eccentricity is less than an allowable value before the high-speed dehydrating operation is started. Despite the determination, large vibration may occur during the high-speed dehydration operation. Therefore, in order to reliably suppress abnormal vibration, it is important to accurately detect the amount of eccentricity. However, simply detecting the amount of eccentricity,
It is not enough to suppress the vibration amplitude of the drum (or outer tub) during the high-speed dehydration operation to a predetermined value or less. This is because the relationship between the actual eccentric amount and the vibration amplitude is not unique and depends on the amount of laundry, that is, the load amount. That is, when the load is large, the inertia force is increased as in the case where the weight of the drum itself is increased, and the influence of the amount of eccentricity is relatively small, so that the vibration amplitude can be small. Conversely, when the load amount is small, even if the amount of eccentricity is the same, the influence becomes relatively large, so that the vibration amplitude becomes large. Therefore, if the load amount is accurately detected and the eccentricity is determined based on the threshold value according to the load amount to determine whether the dehydration start-up is possible or not, the high-speed dehydrating operation is performed in spite of the fact that the eccentric amount is large. Despite being within the eccentric amount that may start up or conversely start high-speed dehydration operation, it is judged that dehydration start-up is impossible and wasteful time is spent relocating laundry Will do.

The dependence of the load on the relationship between the eccentricity and the vibration amplitude is more remarkable as the load is smaller.
In particular, it is desired that the accuracy of load amount detection is high for a small amount of load. In the conventional drum type washing machine, the load amount detection uses, for example, a water level decrease amount due to water absorption of laundry when water is supplied into the drum. However, in such a conventional drum-type washing machine, the accuracy of load detection for a small amount of laundry is not always satisfactory, and at present it is not possible to make a precise determination.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and an object of the present invention is to provide a load amount detecting device capable of accurately detecting a load amount, particularly when the load amount is small. And a drum-type washing machine provided with the same.

[0007]

Means for Solving the Problems and Embodiments of the Invention A drum-type washing machine of the present invention made to solve the above-mentioned problems comprises: a) a drum having a baffle protruding from an inner peripheral wall; A motor for rotationally driving the drum; c) drive control means for increasing the voltage applied to the motor so that the torque at start-up gradually increases from a state where the drum is stopped; and d) a state where the drum is almost stopped. And a load amount determining means for determining a load amount based on an applied voltage when a predetermined rotation speed is reached immediately after starting to rapidly rotate from or an index value corresponding thereto.

In the drum-type washing machine according to the present invention, when the drive control means increases the applied voltage to the motor and the starting torque gradually increases, the laundry in the drum tends to rise from the bottom of the drum. The load on the rotating baffle creates a load on rotation, and the drum rotates only very slowly until the torque overcomes the gravity acting on the laundry. When the torque of the motor increases to overcome the gravity and the drum rotates further, the lump of laundry on the baffle falls over the baffle, and at that moment, the load is suddenly reduced, so that the drum is rapidly reduced. Start spinning. Thus, the applied voltage immediately after the drum has started to rotate rapidly depends on the weight of the laundry on the baffle that had acted just before against the rotation of the drum. Thus, the load amount determining means obtains the applied voltage or the index value corresponding thereto when the rotation speed reaches a predetermined rotation speed immediately after the start of rapid rotation, and determines the load amount according to the value.

The index value is, for example, when the drive control means controls the rotation of the motor by PWM control, the pulse width of the PWM control signal, for example, the time and pulse of one cycle are high level. A duty ratio which is a ratio to a certain period of time can be used, and when the drive control means controls the rotation of the motor by phase control, the phase control angle of the phase control signal may be used. it can.

[0010] By the way, as described above, when the drum is started, the laundry is dropped from the baffle which is going to rise, and the manner of dropping at this time also depends on the cloth quality of the laundry. That is, for example, in the case of chemical fibers such as polyester and nylon, voids are easily generated between the overlapping cloths, and the whole is in a fluffy state even when wet. For this reason, when the baffle rises, the laundry placed thereon is likely to peel off and fall one by one over the baffle. On the other hand, in cloths such as cotton, the overlapping cloths are in close contact and there are few gaps, so even when the baffle rises, the laundry on top is hard to peel off and does not fall over the baffle one by one without falling It tends to fall over the baffle as a whole. For this reason, even if the load is the same, rapid rotation starts with relatively small torque in laundry made of synthetic fibers, whereas laundry made of cotton rotates rapidly without applying a relatively large torque. Do not start.

Therefore, in order to correct such an error caused by the cloth quality of the laundry, the drive control means, after the start of the drum, near a predetermined rotation speed at which the laundry adheres to the inner peripheral wall of the drum by centrifugal force. The motor is driven so that the drum rotates, and the load amount determining means determines the applied voltage of the motor at that time or the index value corresponding thereto and the previously obtained applied voltage of the motor at the time of starting the drum or the index value corresponding thereto. It is preferable that the cloth quality of the laundry is determined based on the difference between the load and the load amount based on a criterion corresponding to the cloth quality.

That is, when the laundry is rotated by sticking to the inner peripheral wall of the drum due to the centrifugal force, the laundry does not move, and the voltage applied to the motor at this time hardly depends on the cloth quality of the laundry. . Therefore, when the laundry is a cloth mainly composed of cotton, the difference between the applied voltage at the time of starting the drum and the applied voltage at the time of rotation is small, or the applied voltage is higher at the time of starting the drum. On the other hand, when the laundry is a cloth mainly composed of chemical fibers, the applied voltage at the time of rotation is considerably higher than the applied voltage at the time of starting the drum. Therefore, the load determining means determines the load of the laundry based on the criterion corresponding to the load, after determining the cloth quality of the laundry.

When the rotation of the motor is controlled by PWM control or phase control, the voltage applied to the motor is affected by fluctuations in the power supply voltage. Therefore, the drum-type washing machine according to the present invention further includes a voltage measurement unit that measures a power supply voltage,
The load amount determining means may be configured to determine the load amount in consideration of the value of the power supply voltage measured by the voltage measuring means. Thereby, even if the power supply voltage fluctuates, the accuracy of detecting the load amount can be secured.

[0014]

According to the drum type washing machine of the present invention,
Since the load amount is determined based on the applied voltage of the motor or the index value corresponding to the torque at the time of starting the drum where the difference due to the load amount is most remarkable, especially when the load amount is relatively small, The load amount can be determined more precisely than the load amount detection method described above. Therefore, if the load thus detected is used, for example, when determining whether or not the eccentric load due to the uneven distribution of the laundry is sufficiently small at the start of the spin-drying operation, the dependency of the load is determined. It is possible to make an accurate judgment in consideration of the above.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a drum type washing machine according to the present invention will be described below with reference to the drawings. FIG. 1 is a side sectional view of the drum type washing machine. The configuration of the drum type washing machine of the present embodiment will be described based on FIG.

An outer tub 2 is suspended by a spring 3 and a damper 4 inside the outer box 1, and a drum 5 for containing laundry is supported by a main shaft 8 inside the outer tub 2. A door 7 for opening and closing the front opening of the outer tub 2 is provided on the front surface of the outer box 1, and laundry is stored inside the drum 5 by opening the door 7. A large number of water holes 6 are provided in the peripheral wall of the drum 5, and water supplied to the outer tub 2 flows into the drum 5 through the water holes 6, and conversely, from the laundry in the drum 5. The dehydrated water is scattered to the outer tub 2 through the water holes 6. On the inner periphery of the drum 5, baffles 9 for scraping up the laundry with the rotation are arranged at a rotation angle of 120 degrees from each other. The main shaft 8 is held by a bearing 10 mounted on the outer tub 2, and a main pulley 11 is attached to a tip of the main shaft 8. A motor 12 is arranged on the lower surface of the outer tub 2, and the rotational driving force of the motor 12 is transmitted to the main pulley 11 via a motor pulley 13 and a V-belt 14. In this embodiment, a DC brushless motor is used as the motor 12.

The ring body of the main pulley 11 has one opening on the circumference, and a rotation sensor 19 composed of a light emitting unit and a light receiving unit is arranged on both sides of the ring body. The rotation sensor 19 detects that the light emitted from the light emitting unit
During one rotation period, the light passes through the opening only once and reaches the light receiving section, and outputs a detection signal (rotation marker) synchronized with the rotation of the drum 5 based on the light receiving signal. Instead of using the optical rotation sensor 19, a magnet is mounted on the drum 5 side, and a reed switch that opens and closes by magnetic force is provided on the outer box 1 or outer tub 2 side, and conducts only once during one rotation period of the drum. The detection signal may be output by a reed switch.

The water supply pipe 15 connected to the external tap is
It is connected to the outer tank 2 via a water supply valve 16. When the water supply valve 16 is opened, water is supplied to the outer tub 2 through the water supply pipe 15. On the other hand, a drainage pump 18 is provided in a drainage pipe 17 connected to the bottom of the outer tub 2, and water accumulated in the outer tub 2 is discharged to the outside by driving the drainage pump 18.

Next, the electrical configuration of the main part of the drum type washing machine will be described with reference to FIG. The control unit 30 is a CPU, R
It is mainly configured by a microcomputer including an OM, a RAM, and the like, and functionally includes a central control unit 31, a PWM control unit 32, an eccentric load detection unit 33, a load amount detection unit 34, and the like. The central control unit 31 includes a ROM in which an operation program for advancing the dehydration process is stored in advance, and in the course of executing the operation program, a target rotation speed of the motor 12 corresponding to a desired drum rotation speed is determined by the PWM control unit 32. To instruct. The power supply voltage detector 44 is provided with a nominal 100 power supply supplied from an external commercial power outlet to the washing machine.
V commercial power supply voltage is detected.

The motor drive section 40 comprises a DC voltage supply section 41 and an inverter circuit 42, and a PWM control section 32
Together, they function as drive control means for the motor 12. A rotation number detector 43 is attached to the motor 12, and a detection signal corresponding to the actual rotation speed of the motor 12 is fed back to the control unit 30. Specifically, the rotation number detector 43 is a pulse encoder, and is configured to generate one pulse signal every time the motor 12 rotates by a predetermined angle.
Twelve pulse signals (this pulse signal is hereinafter referred to as a “revolution number pulse signal”) are output during a period in which the drum 5 makes one rotation. FIG. 6 is a waveform diagram showing an example of the rotation speed pulse signal. When the rotation speed of the motor 12, that is, the drum 5, is high, the rising interval P of the rotation number pulse signal is narrow, and conversely, when the rotation speed of the drum 5 is low, the interval P is wide. As described above, the interval (hereinafter, referred to as “rotation speed pulse width”) P corresponds to the rotation speed of the motor 12 and the drum 5.

FIG. 3 is a basic configuration diagram of the motor drive unit 40 in FIG. In FIG. 3, the DC voltage supply unit 41 is shown as a DC power supply 41a that generates a constant DC voltage Vd. The inverter circuit 42 includes a plurality of switching elements for converting the DC voltage Vd into a variable frequency AC voltage. Each winding of the DC brushless motor 12 is connected to each bridge of these switching elements.
It is turned on / off by the WM control signal.

FIG. 4 is a waveform diagram showing an example of the PWM control signal. The length W2 of one cycle of the PWM control signal (here, 62 pulse units) is a fixed value determined by the switching frequency, and the PWM control unit 32 sets "H" according to the difference between the target rotation speed and the actual rotation speed. The PWM control is executed by changing the level time W1 in units of one pulse unit. That is, when the actual rotation speed is lower than the target rotation speed and it is necessary to increase the rotation speed, the "H" level time W1 is extended, and conversely, the actual rotation speed is higher than the target rotation speed and the rotation speed is decreased. If necessary, the "H" level time W1 is narrowed. PW
The M control unit 32 calculates the actual rotation speed every time a rotation speed pulse signal is obtained from the rotation speed detector 43, and corrects the time width W1 of the PWM control signal as necessary. By such control, a square wave voltage is applied to each winding of the motor 12. In the following description, W1 / W2 is expressed as W1
/ 62 and is referred to as a PWM duty ratio.

In this drum type washing machine, the eccentric load is detected as follows. The rotation speed of the drum 5 is such that the centrifugal force acting on the laundry stored in the drum 5 exceeds the gravity.
When is rotated, the laundry is pressed against the inner peripheral wall surface of the drum 5 and rotates with the rotation of the drum 5. Now, when the laundry is eccentrically loaded and an eccentric load is generated, when the eccentric load is going to be lifted upward through the drum 5 minimum position as shown in a position A in FIG. The acting gravity is in the opposite direction of rotation. Therefore, the gravity acts to decelerate the drum 5. This deceleration effect is maximized when the eccentric load reaches a position near the maximum position of the drum 5. On the other hand, when the eccentric load is conveyed downward after passing through the highest position of the drum 5 as shown in a position B in FIG. 5, the gravity acting on the eccentric load becomes the same direction as the rotation direction. Therefore, the gravity is applied to the drum 5
Acts to accelerate. The effect of this acceleration becomes maximum when the eccentric load reaches near the lowest position of the drum 5.

When a constant target rotation speed is instructed so that the rotation speed of the drum 5 is maintained constant, the PWM control unit 32 changes the time width W1 of the PWM control signal (that is, the PWM duty ratio) to change the motor speed. 12 functions to keep the rotation speed constant. On the other hand, when the PWM control unit 32
If the PWM duty ratio is maintained constant without performing the WM control, the voltage applied to the motor 12 is also constant, and the rotational speed of the drum 5 fluctuates due to the above-described eccentric load. At this time, if the rotation speed pulse width P is plotted with time on the vertical axis, the relationship shown in FIG. 7 is shown. In FIG. 7, the plotted points of the black circles are the data of the actually obtained rotation speed pulse width P, and M is the rotation sensor 1.
9 is a rotation marker generated corresponding to a specific position on the inner circumference of the drum 5, which is obtained by the reference numeral 9.

As shown in FIG. 7, the rotation speed pulse width P fluctuates in synchronization with the rotation of the drum 5. Here, the difference α between the maximum rotation number pulse width Pmax and the minimum rotation number pulse width Pmin within one rotation period of the drum 5 reflects the amount of eccentricity.
Alternatively, the same applies to the ratio between Pmax and Pmin instead of taking the difference. Therefore, the correspondence between the eccentricity and the difference α (or ratio) is checked by performing a number of experiments in advance, and for example, a table is created and stored in the ROM in the eccentric load detecting unit 33. Eccentric load detection unit 33 during eccentric load detection processing
Is the rotation pulse width P given by the rotation detector 43.
Are sequentially stored in the RAM, and the maximum rotation speed pulse width Pmax and the minimum rotation speed pulse width Pmin are found at least when the data during the period during which the drum 5 makes one rotation is collected. Then, the difference α is calculated, and the eccentric amount is acquired with reference to the table.

In the drum type washing machine of this embodiment, after the washing operation or the rinsing operation is completed, the water in the outer tub 2 is drained by the drain pump 18 to perform the dehydration operation. First, a load amount detection process which is a feature of the present invention is executed. Since this load amount detection process is particularly effective when the load amount is small, the load amount detection process is not executed when the load amount is determined to be large in the load amount detection process at the time of water supply, and when the load amount is determined to be small. In addition, it may be executed in order to determine the load amount in finer divisions.

The load detection process will be described below with reference to FIGS.
This will be described with reference to the flowchart of FIG. In the following description, numerical values when the diameter of the drum 5 is 460 mm are taken as an example. However, when the drum diameter is different, it is possible to cope by appropriately changing the numerical values such as the rotation speeds. That is clear.

Immediately before the start of the execution of the load amount detection process, all the laundry is in a state of sufficiently containing water, and is stacked on the bottom of the drum 5 as shown in FIG. First, the PWM control unit 32 sets the PWM duty ratio to 4
/ 62, and controls the motor drive unit 40 so that a voltage corresponding to this is applied to the motor 12 (step S1). Thereafter, the load amount detection unit 34 determines whether 0.4 seconds have elapsed (step S2). If 0.4 seconds have elapsed, the load amount detection unit 34 uses a rotation speed pulse signal obtained from the rotation speed detector 43. It is determined whether the rotation speed of the drum 5 has reached 45 rpm (step S3). If it is determined that the rotation speed of the drum 5 has not reached 45 rpm, P
The WM control unit 32 increases the PWM duty ratio by 1/62, and controls the motor driving unit 40 so that a voltage corresponding to the increase is applied to the motor 12 (step S4). By the processing of steps S1 to S4, initially, when the laundry is stored in the drum 5 even a little, a voltage low enough not to start the rotation of the drum 5 is applied to the motor 12,
The applied voltage is gradually increased until the rotation speed of the drum 5 reaches 45 rpm.

When the motor 12 is started from a stopped state, a large torque is usually required. FIG.
When the laundry is stacked as shown in FIG. 11A, even if the drum 5 starts to rotate slightly, the stacked laundry is placed on the baffle 9 as shown in FIG. The weight acting on the laundry works in a direction that prevents rotation. For this reason, in order for the drum 5 to continue rotating, a larger torque must be applied, and the applied voltage must be increased. When the drum 5 further rotates, the laundry on the baffle 9 slides off the baffle 9 as shown in FIG. Then, the load on the rotation suddenly decreases, and the rotation speed of the drum 5 sharply increases. That is, the rotation speed of 45 rpm is a rotation speed that is reached immediately after the drum 5 starts rotating sharply.

The voltage applied to the motor 12 when the drum 5 starts to rotate smoothly in this way depends on the weight of the laundry on the baffle 9 which has been a load on the rotation until immediately before. That is, when the load amount is large, a larger voltage must be applied when the drum 5 starts rotating,
Conversely, when the load is small, the drum 5 starts rotating without increasing the applied voltage so much. For this reason, the load amount detection unit 34 determines that the rotation speed of the drum 5 is 45 rpm.
Is reached, the PWM duty ratio at that time is changed to a variable A.
It is stored in the memory as 1 (step S5). afterwards,
The PWM control unit 32 sets the target rotation speed to 80 rpm and sets
The WM duty ratio is controlled (step S6). In this drum type washing machine, the equilibrium rotation speed at which the centrifugal force and the gravity acting on the laundry in the drum 5 are substantially balanced is 60 to 65 rpm.
m. Therefore, when the rotation speed of the drum 5 becomes 80 rpm, the laundry sticks to the inner peripheral wall surface of the drum 5 due to the centrifugal force.

Next, it is determined whether or not the variable A1 previously stored in the memory is 16/62 or less (step S).
7) If A1 is equal to or less than 16/62, the PWM control unit 32 sets the PWM duty ratio to A1 and controls the motor drive unit 40 so that a voltage corresponding thereto is applied to the motor 12. (Step S8). Variable A1 is 16
If it is larger than / 62, it is next determined whether or not A1 is equal to or less than 20/62 (step S9).
If it is less than 62, the PWM duty ratio is set to A1-3
/ 62, and controls the motor drive unit 40 so that the voltage corresponding to this is applied to the motor 12 (step S10). If the variable A1 is larger than 20/62, the PWM duty ratio is set to A1-5 / 62, and the motor drive unit 40 is controlled so that a voltage corresponding to the PWM duty ratio is applied to the motor 12 (step S1). S11). The meaning of the processes in steps S7 to S11 will be described later in detail.

After setting the PWM duty ratio as described above, the load amount detector 34 repeatedly determines whether or not two seconds have elapsed (step S12). For example, the maximum rotation speed Smax during one rotation period of the drum 5 is measured only once by the rotation number pulse signal obtained from the rotation number detector 43 (step S13).
Then, it is determined whether or not the maximum rotation speed Smax is equal to or higher than 98 rpm (step S14). If the maximum rotation speed Smax is equal to or higher than 98 rpm, the PWM duty ratio is decreased (for example, 1/1).
62 only), and controls the motor drive unit 40 so that a voltage corresponding to this is applied to the motor 12 (step S
16). On the other hand, if the maximum rotation speed Smax is less than 98 rpm, it is next determined whether or not the maximum rotation speed Smax is less than 91 rpm (step S15).
m, the PWM duty ratio is increased (for example, by 1/62), and the voltage corresponding to this is
Then, the motor drive unit 40 is controlled so as to be applied to the second (step S17). That is, by the processing of steps S12 to S17, the maximum rotation speed Smax of the drum 5 becomes 91 rp.
m and less than 98 rpm.

As described above, when the maximum rotation speed Smax is 91
If it falls within the range of ~ 98 rpm, the PW at this time
The value of the M duty ratio is stored in the memory as a variable A2 (step S18). Thereafter, using the voltage V1 of the commercial power supply detected by the power supply voltage detection unit 44, An
(N = 1, 2) is corrected (step S19). A′n = An × (V1 / 100) Then, using the corrected variables A1 ′ and A2 ′, A3
= A2'-A1 'is calculated (step S20).

As described above, the variable A1 obtained at the start of the drum 5 should depend on the weight of the laundry on the baffle 9 until just before the start of rotation. However, when the laundry has different cloth qualities, the variable A1 does not simply reflect the load of the laundry. It is shown in FIG.
This is because the ease of falling when the laundry falls from above the baffle 9 depends on the cloth quality as shown in FIG. That is,
Generally, for synthetic fibers such as polyester and nylon,
It is easy for air to enter gaps between a plurality of laundry items, and the friction of the fibers themselves is relatively small. Therefore, the overlapping laundry is likely to slide down one by one. On the other hand, in the case of cotton or a fiber similar thereto, it is difficult for air to enter a gap between a plurality of laundry items, and each laundry item is in a state of being in very close contact. Also, the friction of the fibers themselves is usually relatively large. Therefore, the overlapping laundry is less likely to slip off. From such a thing,
Even if the load is the same, the variable A1 is considerably smaller when the chemical fiber is mainly used than when cotton is mainly used.

When all the laundry is rotating while sticking to the inner peripheral wall surface of the drum 5, that is, when rotating at a rotation speed higher than the equilibrium rotation speed, the laundry does not move relative to the motor 12. Is almost unaffected by the quality of the laundry. That is, the variable A2 can be considered to be irrelevant to the quality of the laundry. Therefore, the difference between the variable A2 and the variable A1 is obtained, and by judging the difference, the cloth quality of the laundry can be estimated.

In general, the torque required at the time of starting the drum 5 largely depends on the load. However, once the drum 5 starts rotating, the torque is less dependent on the load due to the influence of inertia and the like. Become. Therefore, if the PWM duty ratio is set to A1 in step S8, S10, or S11 when the variable A1 is considerably large, the torque may be too large, the rotation speed may increase sharply, and greatly exceed 98 rpm. In such a case, not only time is required to reduce the rotation speed to 98 rpm or less, but also abnormal vibration may occur if the eccentric load is large. Therefore, the magnitude of the variable A1 is determined in steps S7 and S9, and if it is determined that the variable A1 is too large, a value obtained by subtracting a predetermined value from the variable A1 in steps S10 and S11 is used as the PWM duty ratio. Thus, a steep increase in rotation speed is avoided.

If A3 has been obtained in step S20, the load amount detector 34 determines whether or not A3 is greater than 0 (step S21). Is determined to be mainly made of cotton, and the process proceeds to step S27. Then, the corrected variable A1 'is 19 /
It is determined whether or not the load is 62 or more. If A1 'is 19/62 or more, it is determined that the load is low (step S28). If A1 'is less than 19/62, it is determined that the small load is smaller than the low load (step S29).

On the other hand, if A3 is greater than 0 in step S21, the laundry is mainly made of chemical fibers or the fabric cannot be determined, but a very small load (usually, only one piece of laundry is used). Is contained).
First, it is determined whether or not the corrected variable A1 'is equal to or less than 11/62 (step S22). If A1' is equal to or less than 11/62, it is determined that the load is a very small load smaller than the small load. (Step S23). A1 'is 11/62
If it is larger, it is next determined whether or not A1 'is 13/62 or less (step S24).
62 or less, that is, 11/62 or 12/62
If it is, it is determined that the load is a small load and the laundry is mainly made of chemical fibers (step S25). A
If 1 'is larger than 13/62, it is determined that the load is low and the laundry is mainly made of chemical fibers (step S26).

As described above, in the drum type washing machine of the present embodiment, the load amount, which was conventionally determined only as a small load, can be divided into three stages of a very small amount, a small amount or a low amount. it can. At the same time, it can be determined whether the fabric is mainly composed of cotton or a chemical fiber.

By determining a threshold value for judging the amount of eccentricity when judging whether or not the high-speed dehydrating operation can be started, in accordance with the load amount thus detected,
The amount of eccentricity can be accurately determined (Japanese Patent Application No. 9-13 / 1997)
No. 4430).

The above embodiment is merely an example, and it is apparent that changes and modifications can be made within the spirit of the present invention. For example, in the above-described embodiment, a DC brushless motor is used as a drive source of the drum and PWM control is performed on the brushless motor. However, an induction motor may be used as a drive source of the drum and so-called phase control may be performed.

[Brief description of the drawings]

FIG. 1 is a side sectional view of a drum type washing machine according to an embodiment of the present invention.

FIG. 2 is an electric configuration diagram of a main part of the drum type washing machine of the embodiment.

FIG. 3 is a basic configuration diagram of a motor drive unit.

FIG. 4 is a waveform chart showing an example of a PWM control signal.

FIG. 5 is a schematic diagram showing a relationship between forces acting on an eccentric load in the drum.

FIG. 6 is a waveform diagram showing an example of a rotation speed pulse signal obtained from a rotation speed detector.

FIG. 7 is a graph showing a change in a rotation speed pulse width when an eccentric load exists.

FIG. 8 is a flowchart of a load amount detection process.

FIG. 9 is a flowchart of a load amount detection process.

FIG. 10 is a flowchart of a load amount detection process.

FIG. 11 is a schematic diagram showing a state inside the drum when the rotation of the drum is started.

[Explanation of symbols]

 2 ... Outer tank 5 ... Drum 12 ... Motor 19 ... Rotation sensor 30 ... Control unit 31 ... Central control unit 32 ... PWM control unit 33 ... Eccentric load detection unit 34 ... Load amount detection unit 40 ... Motor drive unit 41 ... DC voltage supply Unit 42: Inverter circuit 43: Rotation speed detector 44: Power supply voltage detection unit

Continued on the front page F-term (reference) 3B155 AA06 BA03 BA04 BA16 CA02 CA16 CB06 CC17 DC14 KA32 KA33 KB08 KB11 LA03 LB18 LB26 LB35 LC08 LC13 LC33 MA01 MA03 MA06 MA07 MA08 MA09

Claims (5)

[Claims] A) a drum provided with a baffle protruding from an inner peripheral wall; b) a motor for rotating the drum; and c) a motor for starting the drum from a stopped state so as to gradually increase the torque. Drive control means for increasing the applied voltage to the motor, d) based on the applied voltage or the index value corresponding to the applied voltage when the drum reaches a predetermined rotation speed immediately after the drum has almost stopped and immediately starts to rotate. A drum-type washing machine comprising: a load-amount determining unit configured to determine a load amount. 2. The drive control means controls the rotation of the motor by PWM control, wherein the load amount determination means determines a load amount based on a pulse width of the PWM control signal. The drum type washing machine according to claim 1. 3. The drive control means controls the rotation of the motor by phase control, and the load amount determination means determines a load amount based on a phase control angle of the phase control signal. The drum type washing machine according to claim 1, wherein 4. The drive control means drives the motor so that the drum rotates near a predetermined rotation speed such that the laundry sticks to the inner peripheral wall of the drum by centrifugal force after the start of the drum. Determines the cloth quality of the laundry based on the difference between the applied voltage of the motor at that time or the index value corresponding thereto and the previously acquired applied voltage of the motor at the time of starting the drum or the corresponding index value, and The drum type washing machine according to any one of claims 1 to 3, wherein the determination of the load amount is performed based on a criterion according to a cloth quality. 5. The power supply apparatus according to claim 1, further comprising a voltage measuring unit for measuring a power supply voltage, wherein the load amount determining unit determines the load amount in consideration of a value of the power supply voltage measured by the voltage measuring unit. The drum type washing machine according to claim 1.