Method of operating an automatic washing machine and automatic washing machine

Abstract

The invention relates to a method for operating a washing machine comprising an outer tub for receiving washing liquid, a rib-free drum which is rotatably mounted in the outer tub for receiving laundry, a motor for driving the drum, and a control or regulating device. The method has a step of shifting the laundry in the drum, the drum being moved in a right-left movement by means of the motor in said step such that a pendular movement of the laundry is produced at a pendular frequency, the specified pendular amplitude of which is set such that the laundry is dropped, wherein the laundry is dropped from a first region of the drum into a second region of the drum. The invention additionally relates to a corresponding washing machine.

Description

[0001] The invention relates to a method for operating a washing machine and to a washing machine. In particular, the invention relates to a method for operating a washing machine with a tub for holding washing liquid, a drum rotatably mounted in the tub for holding laundry, a motor for driving the drum, and a control or regulating device, wherein the method includes a step for rearranging the laundry in the drum, and to a corresponding washing machine.

[0002] EP 2 113 601 A1, EP 3 505 668 A1, US 10 370 787 B2 and WO 2012 / 020898 A1 describe generic methods.

[0003] Washing machine drums usually have ribs inside them. A rib, also known as a follower, is a part of the drum which, when the drum moves, also sets laundry inside the drum in motion, i.e. carries it along. The rib is usually a raised area in the drum that protrudes from the drum shell and points towards the center of the drum. The laundry in the drum hangs on to this raised area up to a certain height when the drum rotates. Then it falls back down and is thus swirled and rearranged. There are usually several ribs in the drum which are arranged at predetermined intervals from one another. The ribs are essential for rearranging the laundry during a wash program.A typical washing cycle during a wash program consists of rotating the drum clockwise, pausing, rotating the drum counterclockwise, pausing, rotating the drum clockwise, pausing, etc. However, the ribs are additional components that incur costs. Therefore, a ribless drum would be desirable.

[0004] The invention therefore addresses the problem of providing a method for operating a washing machine and a washing machine with a ribless drum that are cost-effective.

[0005] According to the invention, this problem is solved by a method having the features of patent claim 1 and a washing machine having the features of patent claim 8. Advantageous embodiments and further developments of the invention emerge from the following subclaims.

[0006] The advantages achieved with the invention, in addition to its cost-effectiveness, include the fact that the pendulum wash rhythm implemented with the method results in a relatively high washing mechanism, thus enabling relatively fast washing and / or a relatively high washing efficiency, which may be necessary with relatively heavy soiling. At the same time, the wash rhythm allows the laundry to be stratified without the need for swirling ribs, even with a relatively small load.

[0007] The invention relates to a method for operating an automatic washing machine with a tub for holding washing liquid, a ribless drum rotatably mounted in the tub for holding laundry, a motor for driving the drum and a control or regulating device, wherein the method comprises a step for rearranging the laundry in the drum, in which the drum is set in a right-left movement with the aid of the motor in such a way that a pendulum movement of the laundry is caused with a pendulum frequency, the predetermined pendulum amplitude of which is set in such a way that a laundry fall is realized in which the laundry falls from a first area of ​​the drum into a second area of ​​the drum.

[0008] During the development of the washing process technology for a washing machine with a ribless drum, it became apparent that, particularly when the amount of laundry in the drum is relatively small, the laundry items slip when the drum rotates and are not carried along by the drum. This slipping creates a new type of washing mechanism by rubbing against a side of the laundry item facing the drum. However, in order to also apply a washing mechanism to the sides of the laundry items not facing the drum, it is necessary to rearrange the laundry, which is not possible due to the slipping. Using the method according to the invention, the laundry is rearranged in the drum despite the tendency to slip, and a laundry-falling washing mechanism is created.This creates a wash rhythm with a relatively strong washing mechanism by setting the drum in a left-right motion, resulting in a pendulum motion of the laundry so great that it falls. A slight frictional contact between the drum and the laundry is sufficient for this, without causing the laundry to slip inside the drum.

[0009] A ribless drum is a drum that does not have a rib or driver inside. However, it can have other elevations and / or depressions that do not have the shape of the plate-shaped rib or driver. The drum, preferably the drum shell, preferably has depressions and / or elevations other than a rib. It preferably has honeycombs, each of which is designed as an elevation or depression.

[0010] The first area of ​​the drum is an area that lies below the second area of ​​the drum, based on a normal operating position of the washing machine.

[0011] According to the invention, the oscillation frequency is set in the range of -50% to +20% of a calculated oscillation frequency stored in the washing machine, wherein the stored calculated oscillation frequency is determined using the following formula (1) f = g r 2 π where f is the predetermined oscillation frequency, g is the gravitational constant (= 9.81 m / s 2< ), and r is the drum radius of the ribless drum. The drum radius is the inner radius of the drum. Preferably, the oscillation frequency is set at -30% of the oscillation frequency calculated from It. (1) stored in the washing machine. This further ensures that the laundry is carried along sufficiently safely and that a relatively intensive laundry fall is achieved.

[0012] Preferably, the oscillation frequency is set so that the speed has a triangular temporal progression. This ensures that the laundry is transported safely without slipping. The triangular temporal progression is preferably achieved by alternately accelerating the motor with constant acceleration in sections. Since the course of the angle of rotation represents the integral of the speed curve, this curve is nevertheless almost sinusoidal due to the properties of integration (damping of the higher frequency components with -20 dB / decade). An exact sinusoidal curve is not necessary. The triangular temporal progression of the speed has the advantage that it can be implemented with relatively low computing power of the control or regulating device.

[0013] In a preferred embodiment, the predetermined pendulum amplitude is greater than + / - 90°. This further ensures that the laundry falls smoothly. More preferably, the predetermined pendulum amplitude is in the range of + / - 90° to + / - 150°. Even more preferably, the predetermined pendulum amplitude is in the range of + / - 100° to + / - 110°. This further ensures that the laundry is carried along with sufficient safety and that a relatively intensive fall is achieved.

[0014] In a preferred embodiment, the pendulum amplitude is increased from zero to the predetermined pendulum amplitude within a predetermined time. This has the advantage that the pendulum amplitude can be gradually increased until it is so large that the laundry falls.

[0015] Preferably, the predetermined time is a first period of up to 0.5 pendulum periods, preferably up to 0.2 pendulum periods. This causes the laundry to slide at the beginning of the process, thereby achieving a short initial phase with surface friction between the drum and the laundry, which further contributes to the washing effect. Alternatively, the predetermined time is preferably a second period of 1.0 to 2.0 pendulum periods, more preferably 1.5 pendulum periods. This further ensures that the majority of the laundry is removed within this second period without slipping. In a preferred embodiment, the predetermined time depends on a type of laundry, which is determined by setting the washing program.This has the advantage that more delicate laundry can be exposed to less friction than less delicate laundry, while the less delicate laundry can be exposed to a stronger washing mechanism.

[0016] In a preferred embodiment, the predetermined oscillation amplitude is maintained for a predetermined period of time. If the oscillation amplitude is maintained after reaching the predetermined oscillation amplitude, the laundry will continuously rise and fall alternately on the right and left sides, relative to the washing machine's normal operating position. This results in a relatively intensive washing action.

[0017] Furthermore, the invention relates to a washing machine with a tub for holding washing liquid, a ribless drum rotatably mounted in the tub for holding laundry, a motor for driving the drum and a control or regulating device which is designed to carry out a method according to one or more of the embodiments described above.

[0018] The embodiments and advantages described for the method apply accordingly to the washing machine and vice versa.

[0019] The washing machine can be a front-loader or a top-loader. The term "washing machine" also includes a combination appliance such as a washer-dryer. The drum is preferably mounted so that it can rotate in the tub with a horizontal axis of rotation.

[0020] The control or regulating device can be designed as a single or multi-part unit. In addition to controlling the speed of the motor to drive the drum, it also includes additional controls or regulation elements required to execute the wash program.

[0021] An embodiment of the invention is shown purely schematically in the drawings and is described in more detail below. It shows Fig. 1 shows a time course of a rotational speed and an angle in a method according to the invention; and Fig. 2 shows a time course of a rotational speed and an angle in a further method according to the invention.

[0022] Fig. 1 shows a temporal progression of a speed and an angle in a method according to the invention. The temporal progression of the speed is triangular. The triangular shape is achieved by alternately accelerating the motor with constant acceleration in sections. The speed is increased in an acceleration phase until it is varied in the range of + / -150 min -1<. Since the progression of the angle, ie the angle of rotation, represents the integral of the speed progression, this progression is almost sinusoidal due to the properties of the integration (damping of the higher frequency components -20 dB / decade).

[0023] A predetermined pendulum amplitude for generating a laundry fall is initially increased from zero to the predetermined pendulum amplitude within a predetermined time. The predetermined time is a first period of time, which is, for example, 1.5 pendulum periods. The first period represents the acceleration phase, during which a large portion of the laundry is carried along as the drum rotates without slipping. As soon as the predetermined pendulum amplitude of, for example, approximately + / - 100° is reached, the laundry falls. If the predetermined pendulum amplitude is then maintained, the laundry is constantly raised and fallen alternately on the right and left side of the drum, relative to the normal operating position of the washing machine.

[0024] Fig. 2 shows a time course of a speed and an angle in another method according to the invention. Fig. 2 The speed and angle curves shown correspond to those shown in Fig. 1 shown time courses with the difference that the predetermined time is a second period which is zero, and the speed of the drum is varied in the range of +1-100 min -1<, so that the Fig. 1 The acceleration phase described is missing. This means that at the beginning of the process, the laundry slides in the drum, resulting in a brief initial phase with surface friction between the drum and the laundry.

Claims

1. Method for operating a washing machine comprising a suds container for receiving washing liquid, a rib-free drum, which is rotatably mounted in the suds container, for receiving laundry, a motor for driving the drum and an open-loop or closed-loop control device, the method comprising a step for rearranging the laundry in the drum, in which the drum is offset in a right-left movement by means of the motor in such a way that a rocking motion of the laundry is caused at a rocking frequency, the predetermined rocking amplitude of which is set in such a way that a laundry fall is realised, in which the laundry falls from a first region of the drum into a second region of the drum, characterised in that the rocking frequency is set in the range of -50% to +20%, preferably - 30%, of a calculated rocking frequency stored in the washing machine, the stored calculated rocking frequency being calculated using the following formula (1), f = g r 2 π where f is the predetermined rocking frequency, g is the gravitational constant = 9.81 m / s2 and r is a drum radius of the rib-free drum.

2. Method according to claim 1, characterised in that the rocking frequency is set in such a way that the rotational speed has a triangular-shaped time curve.

3. Method according to claim 2, characterised in that the triangular-shaped time curve is realised by alternating acceleration of the motor with constant acceleration in sections.

4. Method according to any of the preceding claims, characterised in that the predetermined rocking amplitude is more than + / - 90°, preferably in the range of + / - 90° to + / - 150°, more preferably in the range + / - 100° to + / - 110°.

5. Method according to any of the preceding claims, characterised in that the rocking amplitude is increased from zero to the predetermined rocking amplitude within a predetermined time.

6. Method according to claim 5, characterised in that the predetermined time is a first time period of up to 0.5 rocking periods, preferably 0.2 rocking periods, or a second time period of 1.0 to 2.0 rocking periods, preferably 1.5 rocking periods.

7. Method according to any of the preceding claims, characterised in that the predetermined rocking amplitude is maintained over a predetermined period of time.

8. Washing machine comprising a suds container for receiving washing liquid, a rib-free drum, which is rotatably mounted in the suds container, for receiving laundry, a motor for driving the drum, and an open-loop or closed-loop control device which is designed to carry out a method according to any of the preceding claims.

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