Domestic dishwashing machine and method

Abstract

The invention relates to a household dishwasher (1) comprising a washing chamber (2), a door (3) attached to the washing chamber (2) in a rotatable manner, a door opening and closing device (17) for the automatic opening and closing of the door (3), and a control unit (31) for controlling the door opening and closing device (17), where the control unit (31) is designed to detect the motor current (I) of a drive element (20) of the door opening and closing device (17) and to assess accordingly whether the door opening and closing device (17) is in working or not working.

Description

[0001] The present invention relates to a household dishwasher and a method for operating such a household dishwasher.

[0002] A dishwasher comprises a wash tub into which the items to be cleaned are placed. A door is hinged to the wash tub, allowing it to be opened and closed. A spring-loaded cable system can be used for the automated opening and closing of the door. To prevent injury to a user from the door opening uncontrollably in the event of damage to the cable system, monitoring of the cable system is advantageous.

[0003] DE 10 2011 050 914 A1 discloses a dishwasher with a machine base and a wash chamber providing a wash compartment, wherein the wash chamber has a wash chamber access opening that can be closed by means of a pivoting door, and with a door spring which is arranged at one end on the door via an intermediate cable pull and at the other end on the machine base. To ensure increased operational reliability with regard to the door spring, the dishwasher includes a breakage sensor for the door spring.

[0004] From earlier application EP 3 698 701 A1, an automatic door opening system suitable for use in a dishwasher is known, comprising at least one rod driven by a bidirectional motor. This rod enables the door to open by exerting a pushing force from one side of the door while moving forward. The time the motor has moved forward is stored, allowing the motor to rotate in reverse for the stored time, thus returning the rod to its starting position. By comparing the motor current with a threshold value, it is possible, for example, to detect obstacles in the door area during the opening process and prevent damage to the door or the door opening system.

[0005] Against this background, one object of the present invention is to provide an improved household dishwasher.

[0006] Accordingly, a household dishwasher is proposed, comprising a wash tub, a door pivotally hinged to the wash tub, a door opening and closing mechanism for automated opening and closing of the door, and a control unit for controlling the door opening and closing mechanism. The control unit is configured to detect the motor current of a drive element of the door opening and closing mechanism and to evaluate whether the door opening and closing mechanism is functional or non-functional.

[0007] By monitoring the motor current, a separate switch or sensor for monitoring the door opening and closing mechanism can be advantageously omitted in a household dishwasher. This reliably prevents user injury from an uncontrolled door opening due to a malfunction in the door opening and closing mechanism.

[0008] Preferably, the wash tub is cuboid in shape and has a loading opening at the front for loading the household dishwasher with items to be washed. This opening can be closed and reopened using the door. The wash tub is supported by a box-shaped base. The door opening and closing mechanism is arranged at least partially within the base. The door can be opened and closed automatically using this mechanism. However, it is also preferably possible to open and close the door manually. The fact that the door is "hinged" on the wash tub means that it is pivotally attached to the wash tub, the base, or the housing of the household dishwasher by means of a hinge.

[0009] The control unit can be part of the door opening and closing mechanism. Dishwasher programs for the household dishwasher can also be stored in the control unit. "Stored" in this context means that the dishwashing programs, or other programs such as a program for evaluating the motor current, are saved within the control unit. The control unit may have a memory module for this purpose. To detect and evaluate the motor current, the control unit may include a microprocessor or similar component. The control unit's suitability for detecting and evaluating the motor current results from the presence of suitable electronic components, such as the aforementioned microprocessor, and from a program stored within the control unit for detecting and / or evaluating the motor current. In particular, the control unit detects a motor characteristic curve of the drive element.In this context, a "motor characteristic curve" refers to the course of the motor current over time.

[0010] The drive element is preferably part of the door opening and closing mechanism. The drive element can be an electric motor. Preferably, the door opening and closing mechanism comprises, in addition to the drive element, a spring element and a cable coupled to the spring element and the door. The drive element is preferably operatively connected to the cable in such a way that the drive element drives the cable. The malfunction of the door opening and closing mechanism can result, for example, from a break in the spring element and / or the cable. A loss of preload in the spring element can also lead to malfunction. However, other components of the door opening and closing mechanism besides the aforementioned can also cause it to malfunction. This, too, can be detected.

[0011] The motor current can be evaluated by comparing the measured motor current with a value stored in the control unit, such as a limit value or a reference motor characteristic curve. If the measured motor current is lower than a target value, the control unit may assume that the spring element and / or the cable is broken, as the drive element would then spin freely without a load, resulting in a lower motor current than in the case of a functioning door opening and closing mechanism.

[0012] According to one embodiment, the control unit is configured to output a signal and / or deactivate the door opening and closing device in the event that the door opening and closing device is inoperative.

[0013] The signal could be, for example, a warning signal output via a user interface. The signal could be visual and / or audible. Even if the door opening and closing mechanism is deactivated, the door can still be opened and closed manually.

[0014] According to another embodiment, the door opening and closing device has a cable coupled to the door and a spring element coupled to the cable, wherein the control unit is configured to evaluate the motor current to determine whether the cable and / or the spring element is functional or non-functional.

[0015] The drive element can be operatively connected to the cable for opening and closing the door. However, the drive element can also be coupled to the door in another way, so that the cable and spring element are not necessarily part of the door opening and closing mechanism.

[0016] According to another embodiment, the household dishwasher further comprises a drive roller driven by the drive element, which is wrapped around the rope to drive the rope.

[0017] The drive pulley can have a cylindrical friction surface on which the rope is preferably wound with 1.25 turns. Power is transmitted from the drive pulley to the rope by friction.

[0018] According to another embodiment, the control unit is configured to control the drive element in a closed state of the door and to detect and evaluate the motor current in the closed state of the door.

[0019] For this purpose, the door is closed manually or automatically. The door can be locked using a door lock. The door lock can be controlled by the control unit.

[0020] According to a further embodiment, the control unit is configured to compare a motor characteristic curve of the drive element with a reference motor characteristic curve and / or a limit value stored in the control unit and, depending on a deviation of the motor characteristic curve from the reference motor characteristic curve and / or the limit value, to recognize whether the door opening and closing device is functional or non-functional.

[0021] The limit value refers to a limit value for the motor current. It can therefore also be called the motor current limit. As mentioned previously, a "motor characteristic curve" describes the behavior of the motor current over time. The control unit may have a tolerance range for the reference motor characteristic curve. If the measured motor characteristic curve lies within this tolerance range, the control unit assumes that the door opening and closing mechanism is intact. If the measured motor characteristic curve lies outside this tolerance range, the control unit assumes that the door opening and closing mechanism is defective. The same applies to the limit value for the motor current. If the measured motor characteristic curve lies below the limit value, it can be assumed that the drive element rotates freely and that the spring element and / or the cable are broken.If the motor characteristic curve is above the limit value, it can be assumed that the door opening and closing device is intact.

[0022] According to another embodiment, the household dishwasher also includes a user interface for operating the door opening and closing device and for outputting a signal as to whether the door opening and closing device is functional or non-functional.

[0023] Preferably, the user interface includes a push button, a touch display, a microphone, a sensor, or other input device. The user interface is also capable of outputting information, for example, in the form of a visual and / or acoustic signal.

[0024] Furthermore, a method for operating such a household dishwasher is proposed. The method comprises the following steps: a) closing the door, b) activating the drive element with the door closed, c) detecting the motor current of the drive element, and d) evaluating the motor current to determine whether the door opening and closing device is functional or non-functional.

[0025] Closing the door in step a) can be done manually or automatically using the door opening and closing device. Steps b) to d) are carried out primarily using the control unit.

[0026] According to one embodiment, in step d) a motor characteristic curve of the drive element is compared with a reference motor characteristic curve stored in the control unit and / or a limit value stored in the control unit.

[0027] As explained previously, depending on the extent of the deviation of the recorded motor characteristic curve from the reference motor characteristic curve or from the limit value, it is determined whether the door opening and closing device is functional or non-functional.

[0028] According to another embodiment, the reference motor characteristic curve is stored in the control unit during a calibration process of the household dishwasher.

[0029] The calibration process can be performed, for example, when putting a household dishwasher into operation. The calibration process can also be repeated at predetermined time intervals.

[0030] The embodiments and features described for the household dishwasher apply accordingly to the proposed method and vice versa.

[0031] Other possible implementations of the household dishwasher and / or the method also include combinations of features or embodiments described previously or subsequently with regard to the exemplary embodiments, even if not explicitly mentioned. In such cases, the person skilled in the art will also add individual aspects as improvements or additions to the respective basic form of the household dishwasher and / or the method.

[0032] Further advantageous embodiments and aspects of the household dishwasher and / or the method are the subject of the dependent claims and the exemplary embodiments of the household dishwasher and / or the method described below. The household dishwasher and / or the method are further explained below with reference to preferred embodiments and the accompanying figures. Fig. 1 shows a schematic perspective view of an embodiment of a household dishwasher; Fig. 2 shows a schematic sectional view of the household dishwasher according to Fig. 1 ; The Fig. 3 shows another schematic sectional view of the household dishwasher according to section line III-III of the Fig. 2 ; Fig. 4 shows a schematic diagram in which the motor current of a drive element for the household dishwasher according to Fig. 1 is applied over time; Fig. 5 shows a schematic timeline of an opening and closing process of a household dishwasher door according to Fig. 1 ; and Fig. 6 shows a schematic block diagram of an embodiment of a method for operating the household dishwasher according to Fig. 1 .

[0033] In the figures, identical or functionally equivalent elements have been given the same reference symbols, unless otherwise indicated.

[0034] The Fig. 1 Figure 1 shows a schematic perspective view of an embodiment of a household dishwasher 1. The household dishwasher 1 comprises a wash tub 2, which can be closed by a door 3, in particular in a watertight manner. For this purpose, a sealing device can be provided between the door 3 and the wash tub 2. The wash tub 2 is preferably cuboid in shape. The wash tub 2 can be arranged in a housing of the household dishwasher 1. The wash tub 2 and the door 3 can form a wash chamber 4 for washing dishes.

[0035] Door 3 is in the Fig. 1 The door 3 is shown in its open position. It can be opened or closed by pivoting it about a pivot axis 5 located at its lower end. The door 3 can be used to open or close a loading opening 6 of the wash tank 2. The wash tank 2 has a base 7, a top 8 opposite the base 7, a rear wall 9 opposite the closed door 3, and two opposing side walls 10 and 11. The base 7, the top 8, the rear wall 9, and the side walls 10 and 11 can, for example, be made of stainless steel. Alternatively, the base 7 can, for example, be made of a plastic material.

[0036] The household dishwasher 1 further comprises at least one dishware holder 12 to 14. Preferably, several, for example three, dishware holders 12 to 14 can be provided, wherein the dishware holder 12 can be a lower dishware holder or a lower basket, the dishware holder 13 an upper dishware holder or an upper basket, and the dishware holder 14 a cutlery drawer. As the Fig. 1 As further shown, the dishware holders 12 to 14 are arranged one above the other in the washing container 2. Each dishware holder 12 to 14 can be selectively moved into or out of the washing container 2. In particular, each dishware holder 12 to 14 can be pushed or moved into the washing container 2 in an insertion direction E and pulled or moved out of the washing container 2 in an extension direction A opposite to the insertion direction E.

[0037] The Fig. 2 Figure 1 shows a schematic sectional view of the household dishwasher. Fig. 3 shows another schematic sectional view of the household dishwasher 1 according to section line III-III of the Fig. 2 The sectional view is shown according to the Fig. 3 compared to the sectional view according to the Fig. 2 rotated 90° counterclockwise. The following refers to the Fig. 2 and 3 Reference was made at the same time.

[0038] The household dishwasher 1 comprises a base support 15, which carries the wash tub 2. The base support 15 can be an injection-molded plastic component. The base support 15 encloses an interior space 16. A door opening and closing device 17 can be accommodated in the interior space 16. The door opening and closing device 17 comprises a cable 18 connected to the door 3, a drive pulley 19 in contact with the cable 18, and a drive element 20, for example an electric motor, which is configured to drive the drive pulley 19 to move the cable 18, thereby causing a pivoting movement of the door 3.

[0039] Furthermore, the door 3 includes a lever section 21 to which a first end section 23 of the rope 18 is connected. The door 3, the drive element 20, and the rope 18 are arranged such that a change in the tensile force F1 applied to the lever section 21 by means of the drive element 20 and the rope 18 causes the pivoting movement of the door 3. For this purpose, the drive pulley 19 is operatively connected to the drive element 20.

[0040] The door 3 is pivotally mounted, for example, on the wash tub 2, the base support 15, or a housing of the household dishwasher 1 (not shown) by means of a hinge 22. The pivot axis 5 is associated with the hinge 22. The drive roller 19 and the cable 18 are arranged such that the transmission of drive force from the drive roller 19 to the cable 18 occurs exclusively by means of frictional engagement. For this purpose, a friction surface 24 of the drive roller 19 is formed between the drive roller 19 and the cable 18. The friction surface 24 can be cylindrical.

[0041] The rope 18 has a wrap angle α around the drive pulley 19 between 360° and 540°, preferably between 400° and 500°, more preferably between 425° and 475°, and even more preferably between 445° and 455°. For example, the wrap angle α is exactly 450°. This can also be described as 1.25 rope wraps around the drive pulley 19. Advantageously, with such a wrap angle α, the maximum tensile force F1 acting on the lever section 21 can be set or limited.

[0042] Furthermore, the door opening and closing device 17 comprises a spring element 25, which is connected to the base support 15 and to the cable 18 and which is designed to at least partially compensate for the weight force G of the door 3. A second end section 26 of the cable 18 is connected to the spring element 25. For example, the spring element 25 is designed as a helical spring or cylindrical spring, and in particular as a tension spring. The spring element 25 comprises a first end section 27, which is connected to the second end section 26 of the cable 18. The spring element 25 also has a second end section 28, which is fixedly connected to the base support 15. If the drive element 20 now drives the drive roller 19 in such a way that the door 3 performs an opening movement, then the spring element 25 is stretched.

[0043] Furthermore, the household dishwasher 1 includes a deflection pulley 30 rotatable about a pivot axis 29, which is designed to deflect the rope 18 between the drive pulley 19 and the door 3. The deflection pulley 30 can be used, for example, to shape the path of the rope 18. For instance, the wrap angle α can be increased or adapted to the geometric boundary conditions of the base support 15 by using the deflection pulley 30.

[0044] Furthermore, the rope 18 and the drive pulley 19 are arranged such that when the opening angle β of the door 3 changes due to a hand force F2 acting on the door 3, the rope 18 slides over the drive pulley 19. This occurs particularly when the spring element 25 is abruptly released, especially when the door 3 is quickly closed by hand force F2, and a spring force F3 acts on the second end section 26 of the rope 18 with the drive pulley 19 blocked. The opening angle β is an angle that is formed between the door 3 and a vertical plane V through which the pivot axis 5 passes. The door opening and closing device 17 is designed, for example, such that an interaction of spring force F3 and weight force G of the door 3 enables slip-free winding of the rope 18 onto the drive roller 19 and unwinding of the rope 18 from the drive roller 19 at every opening angle β of the door 3.

[0045] Furthermore, the door opening and closing device 17 includes a control unit 31, which is configured to control the drive element 20 in such a way as to effect the pivoting movement of the door 3. The control unit 31 is also suitable for supplying a motor current I ( Fig. 4 ) of the drive element 20. For this purpose, the control unit 31 can be coupled to the drive element 20 by means of a signal connection 32. The signal connection 32 can be a data line. The signal connection 32 can also be wireless. For example, the control unit 31 is configured to control the drive element 20 such that the door 3 performs a full opening movement and / or a partial opening movement and / or a full closing movement and / or a partial closing movement. For this purpose, the control unit 31 and the drive element 20 are coupled to each other via the signal connection 32.

[0046] For example, the household dishwasher 1 includes a user interface 33 configured to communicate with the control unit 31 for controlling the drive element 20. A signal connection 34 is provided for this purpose. The signal connection 34 can be a data line. The signal connection 34 can also be wireless. Preferably, the user interface 33 includes a push button, a touch display, a microphone, a sensor, or another input device.

[0047] As the Fig. 3 As shown, the drive element 20 is operatively connected to the drive roller 19 by means of a gear 35, in particular a worm gear. The gear 35 is arranged between the drive element 20 and the drive roller 19. The drive roller 19 is rotated about an axis of rotation 36 by means of the drive element 20 and the gear 35. The drive roller 19 exhibits, for example, rotational symmetry with respect to the axis of rotation 36.

[0048] For example, the gearbox 35 is designed to inhibit the movement of the drive roller 19 when a torque is applied to the drive roller 19 from outside the gearbox 35. This can occur, for instance, when a user manually opens the door 3, causing the spring force F3 to act on the second end section 26 of the rope 18 and thereby apply a torque to the drive roller 19. If, for example, such a spring force F3 exceeds a certain amount, the rope 18 slips over the drive roller 19. Sliding friction then occurs at the friction surface 24. Due to the preload of the spring element 25, the spring force F3 also acts on the rope 18 when the door 3 is completely closed. Consequently, rope friction also occurs at the drive roller 19 in this state.

[0049] With the aid of the door opening and closing device 17, the torque of the drive element 20 is transmitted via the cable 18 or the spring element 25 in automatic operation of the door 3, and in manual operation of the door 3, uncontrolled slamming of the door is prevented by the friction of the cable. Breakage or tearing of the cable 18 and / or the spring element 25 can occur during automatic opening of the door 3 after unlocking a door lock 37 ( Fig. 2 The door 3 could fall into its open position without significant delay and thus uncontrollably. In this case, there is a risk of injury to the user, especially children. This must be prevented.

[0050] This can be prevented by monitoring the door opening and closing device 17. This is done by monitoring the motor current I of the drive element 20.

[0051] The Fig. 4 Figure 1 shows a schematic diagram in which the motor current I of the drive element 20 is plotted against time t. As mentioned previously, the control unit 31 is suitable for detecting the motor current I of the drive element 20. To verify whether there is a break in the spring element 25 and / or the cable 18, it is possible to actuate the drive element 20 with the door 3 closed and to evaluate a motor characteristic curve 38, 39 of the drive element 20. If the door opening and closing device 17 is intact, the drive element 20 must overcome the cable friction force in the form of a load torque. In the case that the spring element 25 and the cable 18 are intact, the Fig. 4 The motor characteristic curve is marked with reference numeral 38. If the spring element 25 and / or the cable 18 is broken, the drive element 20 rotates without load torque. In the Fig. 4 The motor characteristic curve with broken spring element 25 and / or cable 18 is designated by reference numeral 39.

[0052] The control unit 31 detects the motor current I or the motor characteristic curve 38, 39. The control unit 31 is also suitable for evaluating the motor current I or the motor characteristic curve 38, 39. The evaluation can be carried out in such a way that a starting current 40 occurring when the drive element 20 starts up is not used in the motor characteristic curve 38, 39 to assess whether or not a break of the spring element 25 and / or the cable 18 has occurred.

[0053] Furthermore, for example, during the calibration of the door opening and closing device 17, a reference motor characteristic curve 41 can be recorded and stored in the control unit 31. In this case, the control unit 31 compares the respective motor characteristic curve 38, 39 with the reference motor characteristic curve 41. The calibration can be performed, for example, at predetermined time intervals. If the motor characteristic curve 38, 39 deviates too much from the reference motor characteristic curve 41, it can be assumed that the spring element 25 and / or the cable 18 is damaged. The permissible deviation of the motor characteristic curve 38, 39 from the reference motor characteristic curve 41 can be stored in a tolerance field in the control unit 31.

[0054] Furthermore, a limit value 42 for the motor current I can be stored in the control unit 31. If the motor characteristic curve 38 is above the limit value 42, it can be assumed that the spring element 25 and the cable 18 are intact. If the motor characteristic curve 39 is below the limit value 42, it can be assumed that the spring element 25 and / or the cable 18 is broken. In this case, corresponding information, in particular a warning signal, can be output via the user interface 33. Furthermore, the information can also trigger the deactivation of the automated opening of the door 3. Therefore, monitoring of the spring element 25 and / or the cable 18 using an additional switch or sensor can be omitted.

[0055] This evaluation of the motor current I is fundamentally possible in both directions of rotation of the drive element 20. Preferably, however, the motor current I is evaluated in the closing direction of the door 3; in this case, a door seal surrounding the loading opening 6 acts as a stop for the movement of the door 3. If the evaluation of the motor current I is carried out in the opening direction of the door 3, it is necessary that the door lock 37 is not unlocked.

[0056] Monitoring the motor current I can be used not only to monitor the spring element 25 and / or the cable 18, but also, for example, to monitor whether the door 3 is fully open or not. In this case, the door 3 rests against a mechanical stop in its fully open position. This results in a peak in the motor current I, which can be used to determine whether the door 3 is fully open or not. This eliminates the need for an additional limit switch to monitor the end position of the door 3. Furthermore, the motor current I can be measured continuously during a closing or opening operation of the door 3.

[0057] The Fig. 5 Figure 1 schematically illustrates, using a timeline as an example, how the monitoring of the motor current I can be carried out. At time t1, door 3 is opened manually or automatically. At time t2, door 3 is closed again manually or automatically. Immediately after door 3 closes, i.e., at time t2, the drive element 20 is activated and the motor current I is monitored. If the spring element 25 and the cable 18 are intact, the motor characteristic curve 38 results according to the... Fig. 4 If the spring element 25 and / or the cable 18 is broken, the motor characteristic curve 39 results according to the Fig. 4 In this case, the control unit 31 outputs the information that the spring element 25 and / or the rope 18 are damaged.

[0058] Door 3 is reopened manually or automatically at time t3. The motor current I is not monitored for a period Δt between time t2 and time t3, as the spring element 25 is relaxed to its preload during this period Δt. Since a breakage of the spring element 25 and / or the cable 18 is therefore highly unlikely during this period Δt, monitoring of the motor current I is unnecessary. At time t4, door 3 is closed again manually or automatically. Immediately after door 3 closes at time t4, the motor current I is analyzed as previously explained.

[0059] In addition, by means of continuous monitoring of the motor current I, it is also possible to detect other wear of the door opening and closing device 17, which manifests itself through an increased consumption of the motor current I of the drive element 20, and to provide corresponding information to the user.

[0060] The Fig. 6Figure 1 shows a schematic block diagram of an embodiment of a method for operating a household dishwasher 1. In step S1, the door 3 is closed manually or automatically. In step S2, the drive element 20 is activated by the control unit 31 while the door 3 is closed. Simultaneously, in step S3, the motor current I or the motor characteristic curve 38, 39 of the drive element 20 is recorded. In step S4, the control unit 31 evaluates the motor current I or the motor characteristic curve 38, 39 to determine whether the door opening and closing device 17 is functional or non-functional. The door opening and closing device 17 is non-functional, for example, if the spring element 25 and / or the cable 18 is broken.

[0061] As mentioned above, in the household dishwasher 1 it is advantageous to dispense with a separate switch or sensor for monitoring the door opening and closing device 17 or the spring element 25 and / or the rope 18.

[0062] Although the present invention has been described using exemplary embodiments, it can be modified in many ways. Reference symbols used:

[0063] 1 Household dishwasher 2 Wash tub 3 Door 4 Wash chamber 5 Swivel axis 6 Loading opening 7 Floor 8 Ceiling 9 Back panel 10 Side panel 11 Side panel 12 Dishwasher holder 13 Dishwasher holder 14 Dishwasher holder 15 Base support 16 Interior 17 Door opening and closing device 18 Cable 19 Drive roller 20 Drive element 21 Lever section 22 Hinge 23 End section 24 Friction surface 25 Spring element 26 End section 27 End section 28 End section 29 Rotary axis 30 Deflection roller 31 Control unit 32 Signal connection 33 User interface 34 Signal connection 35 Gearbox 36 Rotary axis 37 Door lock 38 Motor characteristic curve 39 Motor characteristic curve 40 Starting current 41 Reference motor characteristic curve 42 Limit value A Extension direction E Insertion direction F1 Tensile force F2 Hand force F3 Spring force G Weight force I Motor current S1 Step S2 Step S3 Step S4 Step t Time t1 Time point t2 Time point t3 Time point t4 Time point V Vertical plane α Wrap angle β Opening angle Δt Time period

Claims

1. Household dishwasher (1) with a dishwasher cavity (2), a door (3) attached pivotably to the dishwasher cavity (2), a door opening and closing device (17) for the automated opening and closing of the door (3), and a control unit (31) for actuating the door opening and closing device (17), wherein the control unit (31) is designed to detect a motor current (I) of a drive element (20) of the door opening and closing device (17) and, on this basis, to evaluate whether the door opening and closing device (17) is functional or non-functional.

2. Household dishwasher according to claim 1, characterised in that the control unit (31) is designed to output a signal and / or to deactivate the door opening and closing device (17) in the event that the door opening and closing device (17) is non-functional.

3. Household dishwasher according to claim 1 or 2, characterised in that the door opening and closing device (17) has a cable (18) coupled to the door (3) and a spring element (25) coupled to the cable (18), wherein the control unit (31) is designed to evaluate the motor current (I) in order to establish whether the cable (18) and / or the spring element (25) is functional or non-functional.

4. Household dishwasher according to claim 3, further comprising a drive roller (19), driven by the drive element (20), around which the cable (18) is wrapped so as to be driven.

5. Household dishwasher according to one of claims 1 - 4, characterised in that the control unit (31) is designed to actuate the drive element (20) in a closed state of the door (3) and to detect and evaluate the motor current (I) in the closed state of the door (3).

6. Household dishwasher according to one of claims 1 - 5, characterised in that the control unit (31) is designed to compare a motor characteristic curve (38, 39) of the drive element (20) with a reference motor characteristic curve (41) stored in the control unit (31) and / or a limit value (42) stored in the control unit (31) and to identify, as a function of a deviation of the motor characteristic curve (38, 39) from the reference motor characteristic curve (41) and / or the limit value (42), whether the door opening and closing device (17) is functional or non-functional.

7. Household dishwasher according to one of claims 1 - 6, further comprising a user interface (33) for operating the door opening and closing device (17) and for outputting a signal indicating whether the door opening and closing device (17) is functional or non-functional.

8. Method for operating a household dishwasher (1) according to one of claims 1 - 7, with the following steps: a) closing (S1) the door (3), b) actuating (S2) the drive element (20) when the door (3) is closed, c) detecting (S3) the motor current (I) of the drive element (20), and d) evaluating (S4) the motor current (I) in order to determine whether the door opening and closing device (17) is functional or non-functional.

9. Method according to claim 8, characterised in that, in step d), a motor characteristic curve (38, 39) of the drive element (20) is compared with a reference motor characteristic curve (41) stored in the control unit (31) and / or a limit value (42) stored in the control unit (31).

10. Method according to claim 9, characterised in that the reference motor characteristic curve (41) is stored in the control unit (31) during a calibration procedure of the household dishwasher (1).