DISHWASHERS WITH TRANSPORT DEVICE

Abstract

A dishwasher with a transport device determines an estimated value for a deformation force of the transport device on one or more baskets or on a transport belt based on a motor current determined by a current determination unit, a movement speed of the one or more baskets or the transport belt, a movement acceleration of the one or more baskets or the transport belt, and one or more transport device parameters. The dishwasher deactivates a motor of the transport device if the estimated value meets a threshold condition based on one or more dishwasher parameters.

Description

[0001] The present invention relates to a dishwasher with a transport device.

[0002] For conveyor dishwashers with belts or baskets, overload cut-out units are known as machine protection. These include, for example, mechanical slip clutches, safety clutches, or sensing via torque shears that work against a spring. However, the disadvantage of these units is that they require wear-prone mechanical components and that the overload cut-out units always trigger at the same load throughout the entire application. Furthermore, the production of such systems is costly.

[0003] DE 101 06 206 A1 describes a device for regulating a conveyor belt in a conveyor belt system. The device for regulating a conveyor belt uses a sensor to measure the position of the conveyor belt without contact and evaluates it in such a way that the position of the conveyor belt relative to the sensor is converted into an electrical value proportional to the distance. A control system with a device converts this signal to adjust the conveyor elements for belt steering.

[0004] It is an object of the present invention to provide a dishwasher with a transport device in order to improve user-friendliness taking into account the desired applications.

[0005] The above object is achieved by a dishwasher according to claim 1 and a dishwasher according to claim 2. Claims 3 to 18 relate to particularly advantageous implementations of the dishwasher according to claim 1 and the dishwasher according to claim 2.

[0006] The present invention relates to a dishwasher comprising a transport device and a current determining unit.

[0007] The transport device comprises a transport element, a motor, and an inverter. The transport element is configured to move one or more baskets for dishes along a transport direction or to move a transport belt or conveyor belt or transport belt for dishes in a circumferential direction. The transport element can, for example, comprise one or more drive rollers, a gear, and / or other mechanical components. The transport element can, in particular, be configured to move the one or more baskets relative to a frame or a housing of the dishwasher or relative to a component that is immovably arranged relative to the frame or the housing. The motor is configured to drive the transport element.In particular, the motor can transmit a torque to the transport element, so that the transport element exerts a force on the one or more baskets or the transport belt, thereby moving the one or more baskets along the transport direction or moving the transport belt in the direction of rotation. The converter is configured to convert an input voltage or mains voltage into an output voltage and supply the output voltage to the motor.

[0008] The current determination unit is configured to determine a motor current of the motor. The current determination unit comprises, in particular, a current sensor configured to measure the motor current of the motor. The motor current can, in particular, be a Q current of the motor (i.e., a current in the Q axis (quadrature axis), or a torque-generating current obtained from the Park transformation of the currents through the motor phases).

[0009] The dishwasher or a controller or control unit of the dishwasher is configured to determine an estimated value for a deformation force of the transport device or the transport element on the one or more baskets or on the transport belt based on the motor current determined by the current determination unit, a movement speed or conveying speed of the one or more baskets along the transport direction or a movement speed of the transport belt in the direction of rotation, a movement acceleration of the one or more baskets along the transport direction or a movement acceleration of the transport belt in the direction of rotation, and one or more transport device parameters. The control can be implemented by software and / or hardware components. The estimated value is also referred to below as the power score.The deformation force can, in particular, be a force acting on the one or more baskets or the conveyor belt in the direction of transport. The deformation force can be a component of a total force exerted by the transport device or transport element on the one or more baskets or the conveyor belt. The total force can be a sum of the deformation force and an acceleration force used to accelerate the one or more baskets along the direction of transport or the conveyor belt in the direction of rotation. The deformation force can be opposed to a blocking force or a frictional force, in particular a static or sliding friction force, which acts on the one or more baskets or the conveyor belt in the event of a blockage or disruption of the movement of the one or more baskets or the conveyor belt.The movement speed of the one or more baskets along the transport direction or the transport belt in the direction of rotation can in particular correspond to a speed of the motor or increase with the speed of the motor or be proportional to the speed of the motor. The speed of the motor can correspond to the output voltage of the inverter or increase with the output voltage of the inverter or be proportional to the output voltage of the inverter. The movement acceleration can be determined via a relationship between the movement speed and a target speed for the movement of the one or more baskets along the transport direction or the transport belt in the direction of rotation, as described in more detail below. The one or more transport device parameters can be specific to the respective transport device and in particular depend on the type of transport device (e.g.The dishwasher can, in particular, be configured to determine the estimated value as a function of or as a function of time or a time variable. The estimated value, at any given time, can be based on the motor current determined by the current determination unit at that time, the movement speed at that time, the movement acceleration at that time, and the one or more transport device parameters. The one or more transport device parameters can, in particular, be time-independent.

[0010] The dishwasher or the dishwasher's controller or control unit is configured to shut down the motor or reduce the inverter's output voltage if or when a threshold condition based on one or more dishwasher parameters is met. The dishwasher can shut down the motor by setting the inverter's output voltage to zero.The threshold condition is met if: the estimated value or the amount of the estimated value exceeds a first threshold based on the one or more dishwasher parameters or has exceeded it for a first period of time (level-based overload detection) and / or a temporal increase or an amount of a temporal increase in the estimated value or the amount of the estimated value exceeds a second threshold based on the one or more dishwasher parameters or has exceeded it for a second period of time (gradient-based overload detection).

[0011] The dishwasher according to the invention has the advantage that the motor shutdown or the reduction of the converter's output voltage is not based on a mechanical force or torque measurement, but rather on an estimate of the deformation force based, among other things, on the motor current determined by the current determination unit. This allows for a reduction in the number of mechanical components subject to wear, resulting in a more robust machine with a longer service life. Furthermore, manufacturing costs can be reduced.

[0012] Furthermore, in the dishwasher according to the invention, the motor is switched off or the converter output voltage is reduced not at the same load as in conventional dishwashers, but rather in accordance with the relevant parameters, in particular the movement speed, the movement acceleration, one or more transport device parameters, and one or more dishwasher parameters. The threshold condition and thus the switch-off point can be set specifically for the customer. Thus, depending on these parameters, a variable switch-off point for the motor during operation can be defined. In particular, the transport device parameters are used, which can be dependent on the specific transport device.In addition, the shutdown thresholds can be adapted to each machine-specific requirement, as the base load depends on the length of the machine, which in turn determines the maximum load and the static or sliding friction that must not yet lead to shutdown. Transient effects are also taken into account, in particular the acceleration of the transport system from a standstill. As static friction must be overcome, different parameters apply to determining the estimated value at this time than during uniform movement. This means that the motor can be switched off or the converter output voltage reduced variably and at an early stage in order to avoid or reduce consequential damage to the dishwasher, the transport device, the baskets or the transport belt, or the dishes. This also helps prevent injury to a user if, for example, a part of the user's body comes into contact with the transport device.becomes trapped in the transport device, causing a blockage. In this case, the dishwasher can be shut off in time before excessive force is exerted on the body part, thus preventing injury to the user. Furthermore, this also allows the motor to be larger without risking damage, for example, from a blockage, making the dishwasher more efficient and powerful.

[0013] Furthermore, the advantages described above can also be achieved in the case of technical limitations of the transport device, in particular if torque control cannot be implemented by the transport device, for example, due to pre-configured software components that do not include torque control. In this case, however, the software component used can provide access to internal variables or parameters that, as described above, allow indirect conclusions to be drawn about the force of the transport system. The estimated value or power score exhibits a sufficient correlation with the force in the transport direction to enable a threshold-based shutdown mechanism as described above.

[0014] If the dishwasher shuts off the motor when the threshold condition is met, this has the advantage of preventing damage to the motor or other components of the dishwasher or the dishes. For example, a signal can be sent to the user that the blockage must first be cleared before the dishwasher can continue operating.If the dishwasher reduces the inverter's output voltage when the threshold condition is met, this has the advantage that by reducing the inverter's output voltage, the motor speed and thus the force acting on the one or more baskets or the conveyor belt can be reduced. This allows the dishwasher to continue operating even in the event of a malfunction without the force acting on the one or more baskets or the conveyor belt becoming excessive, thus preventing damage to the motor or other components of the dishwasher or the dishes. The use of the first or second time periods in the threshold condition also has a filtering function: it can compensate for noise and short overload peaks that may occur erroneously.

[0015] In summary, the dishwasher according to the invention increases robustness and efficiency as well as user-friendliness and safety and reduces manufacturing costs.

[0016] In a preferred embodiment, the dishwasher further comprises a voltage determination unit for determining the input voltage of the inverter, and the estimated value for the deformation force is further based on the input voltage of the inverter determined by the voltage determination unit.

[0017] This allows unwanted voltage fluctuations to be taken into account when determining the estimated value. Furthermore, the dishwasher according to the invention can be operated with different mains voltages, for example, in different countries with different mains voltage standards. This increases user-friendliness.

[0018] In particular, the dishwasher can be calibrated to determine one or more transport device parameters. For this purpose, for example, a force sensor can measure a deformation force exerted by the transport element on a test specimen during a calibration process. At the same time, the motor current during the calibration process, optionally the input voltage of the converter during the calibration process, a speed of movement of the test specimen along the transport direction, and an acceleration of the movement of the test specimen through the transport element can be determined. The transport device parameters can then be adjusted or optimized so that the estimated value for the deformation force corresponds to the measured deformation force. The process variables used to calculate the force value can be recorded electronically.Running through different load scenarios (transport speed, voltage, loads from washware, etc.) allows the Q-current to be mapped onto the force sensor curve with sufficient accuracy by translation and scaling.

[0019] In particular, the estimated value or the amount of the estimated value can be greater the greater the amount of the motor current is. In addition or alternatively, the estimated value or the amount of the estimated value can be greater the greater the input voltage or an amount or amplitude of the input voltage is. In addition or alternatively, the estimated value or the amount of the estimated value can be greater the greater the movement speed of the one or more baskets along the transport direction or of the transport belt in the direction of rotation is. In addition or alternatively, the estimated value or the amount of the estimated value can be smaller the greater (with all other parameters being the same, in particular the same motor current, the same input voltage and the same movement speed) the movement acceleration of the one or more baskets along the transport direction or of the transport belt in the direction of rotation is.The estimated value may in particular depend on an acceleration state, for example on whether the one or more baskets or the conveyor belt are accelerated, moved uniformly or decelerated by the conveyor device, or are stationary, as described below.

[0020] This allows the deformation force of the transport device on the one or more baskets or the conveyor belt to be estimated with particular precision, further enhancing user-friendliness. These advantages are based in particular on the fact that the motor current already contains the desired information about the torque or deformation force, but is influenced by the motor speed (corresponding to the movement speed of the one or more baskets or the conveyor belt), the inverter input voltage, and the movement acceleration. These can thus be interpreted as "disturbance factors" that are suppressed by the modeling described above to enable the precise and efficient shutdown described above.In particular, as described above, the total force of the transport device or transport element on the one or more baskets or the transport belt can be a sum of the deformation force and an acceleration force used to accelerate the one or more baskets along the transport direction or the transport belt in the direction of rotation. The acceleration force must therefore be subtracted from the total force in order to obtain a precise estimate of the deformation force. Only an excessively high value of the deformation force should lead to a shutdown of the motor. Therefore, it is advantageous that the estimated value for the deformation force is smaller the greater (with all other parameters being equal) the acceleration of movement of the one or more baskets along the transport direction or the transport belt in the direction of rotation.

[0021] The one or more dishwasher parameters can comprise one or more of the following parameters: a type of dishwasher; a number of baskets or a length of the conveyor belt; an actual load weight of the dishwasher (in particular a current load weight in a washing process, i.e. the weight of the load of wash ware or dishes that are arranged in the one or more transport baskets or on the conveyor belt and are cleaned in the washing process) or an average load weight (load weight in an average washing process, which can be preset for the customer or entered by the user, e.g.lower average load weight when using the dishwasher to wash light plastic cups and higher average load weight when using the dishwasher to wash heavy china) or a maximum load weight (a maximum permissible load weight); and a duration or number of wash cycles by the dishwasher since the dishwasher was first used.

[0022] In particular, the first threshold and / or the second threshold can be higher the greater the number of baskets or the length of the conveyor belt and / or the greater the average load weight or the maximum load weight of the dishwasher. This has the advantage that, in dishwashers with a larger number of baskets or a greater length of the conveyor belt and / or a larger average or maximum load, greater forces act on the one or more baskets or the conveyor belt in the transport direction, even during trouble-free operation, so that shutdown due to a blockage or malfunction may only occur at a higher threshold in order to ensure continuous and safe operation of the dishwasher and thus increase user-friendliness.

[0023] Furthermore, the dishwasher can comprise a load determination unit for determining the actual load weight of the dishwasher, and the first threshold value and / or the second threshold value can be higher the larger the actual load weight determined by the load determination unit. This has the advantage that with a larger actual load weight, greater forces act on the one or more baskets or the conveyor belt in the transport direction, even during trouble-free operation, so that shutdown due to a blockage or malfunction may only occur at a higher threshold value to ensure continuous and safe operation of the dishwasher.

[0024] Furthermore, the dishwasher can comprise an operating time determination unit for determining a time duration or a number of wash cycles of the dishwasher since the dishwasher was first put into operation, and the first threshold value and / or the second threshold value can be greater the greater the time duration or number of wash cycles determined by the operating time determination unit. This has the advantage that in dishwashers that are in operation for a longer period of time or already have a higher number of wash cycles, e.g. due to greater wear, greater forces, in particular frictional forces, act on one or more baskets or the conveyor belt in the transport direction even during trouble-free operation, so that shutdown due to a blockage or malfunction may only occur at a higher threshold value in order to ensure continuous and safe operation of the dishwasher.

[0025] In a preferred embodiment, if the threshold condition is met, the dishwasher is configured to switch off the motor, and the transport device or transport element is configured to move the one or more baskets back in a direction opposite to the transport direction, in particular by a predetermined transport distance, or to move the transport belt back in a direction opposite to the direction of rotation, in particular by a predetermined rotation distance. By moving back, the deformation force on the one or more baskets or the transport belt is reduced or eliminated in the event of a blockage, so that damage to the one or more baskets or the transport belt or other components of the dishwasher or the dishes is prevented, thus increasing user-friendliness.

[0026] The estimated value for the deformation force can in particular be based on an effective current, wherein the effective current is a sum of the motor current and a correction current, wherein the correction current depends linearly on the input voltage of the converter.

[0027] In particular, the effective current (I eff ) in the following relationship to the motor current (I q ), the input voltage (U in ) of the converter, a zeroth transport device parameter (C o ) and a first transport device parameter (C1): Ieff=Iq+C0+C1*Uin.

[0028] Furthermore, the estimated value can depend linearly on the motor current or the effective current. The estimated value can also depend linearly on the movement speed. In particular, one or more or all of the following relationships i) to iv) can be satisfied: i) If the movement of the one or more baskets along the transport direction or the movement of the conveyor belt in the direction of rotation is uniform or even, or the movement speed is constant (in particular if the target speed of the movement is equal to the (actual, current) movement speed or lies within a narrow range around the (actual, current) movement speed, e.g. corresponding to a difference in the speed of the motor of maximum ± 20 rpm), the estimate may be a uniformity estimate (P uni ) which is related to the effective current (I eff ), the movement speed (v), a second transport device parameter (C2), a third transport device parameter (C3) and an eighth transport device parameter (C8): Puni=C2+C3*Ieff+C8*v. (ii) If the movement of the one or more baskets along the transport direction or the movement of the conveyor belt in the direction of rotation is accelerated (in particular if the target speed of the movement is higher or significantly higher than the (actual, current) movement speed, e.g. corresponding to a motor speed at least 20 rpm higher), the estimated value may be an acceleration estimated value (P acc ) which is related to the effective current (I eff ), the movement speed (v), a fourth transport device parameter (C4), a fifth transport device parameter (C5) and a ninth transport device parameter (C9): Pacc=C4+C5*Ieff+C9*v. iii) If the movement of the one or more baskets along the transport direction or the movement of the conveyor belt in the direction of rotation is delayed (in particular if the target speed of the movement is lower or significantly lower than the (actual, current) movement speed, e.g. corresponding to a motor speed lower by at least 20 rpm), the estimated value may be a delay estimated value (P dec ) which is related to the effective current (I eff ), the movement speed (v), a sixth transport device parameter (C6), a seventh transport device parameter (C7) and a tenth transport device parameter (C 10 ) stands: Pdec=C6+C7*Ieff+C10*v. iv) If the speed of movement is zero or small (e.g. corresponding to a motor speed of ± 20 rpm or less), the estimate may be a standstill estimate (P still), where the standstill estimate (P still ) is equal to or substantially equal to zero: Pstill=o.

[0029] The above calculations of the effective current and the estimated value, particularly in the various acceleration states, have the advantage that the deformation force of the transport device on the one or more baskets or the conveyor belt is estimated particularly precisely, thus further increasing user-friendliness. If, as described above, the movement speed, the input voltage of the converter, and the acceleration are interpreted as "disturbance factors" of the motor current, which in itself already contains the desired information about the torque or the deformation force, these "disturbance factors" are particularly efficiently suppressed by the linear modeling described above, enabling the precise and efficient shutdown described above. Furthermore, the linear calculation of the estimated value reduces the (particularly numerical) computational effort and thus the cost of the dishwasher.

[0030] Note that alternatively in equations (2) to (5) the motor current (I q ) instead of the effective current (I eff ) can be used. This further simplifies the above calculation and is particularly useful when the input voltage is constant or known in advance and does not need to be determined by the dishwasher.

[0031] These and other features and advantages of the invention will become clear from the accompanying drawings, which show particularly advantageous embodiments. They show: Fig. 1 shows an operation of a dishwasher according to an embodiment of the present invention; Fig. 2A illustrates operation of a dishwasher according to an embodiment of the present invention with level-based overload detection; Fig. 2B illustrates operation of a dishwasher according to an embodiment of the present invention with gradient-based overload detection; Fig. 3 shows an operation of a dishwasher according to an embodiment of the present invention with level and gradient-based overload detection.

[0032] Fig. 1 shows an operation of a dishwasher according to an embodiment of the present invention. The dishwasher comprises a transport device, a current determination unit, a voltage determination unit, and a controller 10. The transport device comprises a transport element for moving one or more baskets for dishes along a transport direction or for moving a transport belt for dishes in a circumferential direction; a motor for driving the transport element; and an inverter configured to convert an input voltage into an output voltage and supply the output voltage to the motor. The current determination unit is configured to determine a motor current (I q) of the motor. The voltage determination unit is configured to determine the input voltage of the converter (i.e., the mains voltage). The controller 10 is configured to determine an estimated value (P) for a deformation force of the transport device on the one or more baskets or on the transport belt based on the motor current determined by the current determination unit, the input voltage of the converter determined by the voltage determination unit, a movement speed of the one or more baskets along the transport direction or the transport belt in the direction of rotation, a movement acceleration of the one or more baskets along the transport direction or the transport belt in the direction of rotation, and one or more transport device parameters. The controller 10 is further configured to switch off the motor (“STOP” in Fig. 1) if or as soon as a threshold condition based on one or more dishwasher parameters is met. In this embodiment, the threshold condition is met if: the estimated value exceeds a first threshold (P1) based on the one or more dishwasher parameters (P > P1) or has exceeded it for a first period of time; and a temporal increase (dP / dt) of the estimated value exceeds a second threshold (P2) based on the one or more dishwasher parameters (dP / dt > P2) or has exceeded it for a second period of time. The threshold condition in this case is therefore "P > P1 and dP / dt > P2", as in Fig. 1, so that this dishwasher implements level- and gradient-based overload detection. Note that the threshold condition can alternatively be "P > P1" (only level-based overload detection) or "dP / dt > P2" (only gradient-based overload detection). The controller 10 is further configured not to turn off the motor ("GO" in Fig. 1) if the threshold condition is not met (P ≤ P1 or dP / dt ≤ P2). The transport device can further be configured to move the one or more baskets back along a direction opposite to the transport direction or to move the transport belt back in a direction opposite to the direction of circulation ("BACK" in Fig. 1). Especially in a conveyor dishwasher with a drive belt, the belt can be retracted by a defined distance immediately after a blockage is detected, without any operator input, to release the built-up tension.

[0033] In other words, the power consumption of the drive is evaluated using the Q-Current model-based estimate or power score. To generate the power score, a model is used for four different states in which the speed-controlled drive system can be: acceleration, steady motion, deceleration, and standstill. Acceleration is defined by the absolute target speed being higher than the absolute true speed. Deceleration is defined by the absolute target speed being lower than the absolute true speed. Steady motion is defined by the target speed being within a narrow range of the true speed (± 20 rpm). Standstill is defined by both the target speed and the actual speed being zero.A change in rotation direction is considered separately and is treated as a deceleration to 0 rpm and an acceleration to the new target speed in the opposite direction. Formulas (1) to (5) as given above describe the model. The power score is a piecewise defined function that selects the output of (2), (3), (4), or (5) depending on the current state of the drive system. The vector of transport device parameters C. i (i=0, 1, ..., 10) is available to the frequency converter via a CAN interface.

[0034] The control system 10, in particular the control software, contains the following elements: Current consumption (I q ) and calculation of the estimated value P for the deformation force. The estimated value P or the temporal increase of the estimated value is monitored by the logic, which is Fig. 1. The machine's control software or the frequency converter compares P with the first threshold value P1 specified in the software or compares dP / dt with the second threshold value P2 specified in the software. If these two maximum values are exceeded, the control system triggers the belt to stop ("STOP"). Optionally, the belt moves back a defined distance ("BACK"). If the error message displayed is acknowledged ("ACKNOWLEDGED"), the motor can start up again. Alternatively, the software only triggers when P or dP / dt is exceeded for a defined period of time. These threshold values can be varied during calibration of the dishwasher or by a user. This can be used to compensate for the machine length and any shift in the maximum threshold value over the machine's service life.

[0035] Fig. 2A shows an operation of a dishwasher according to an embodiment of the present invention with level-based overload detection. Fig. 2B shows an operation of a dishwasher according to an embodiment of the present invention with gradient-based overload detection. That is, in Fig. 2A or Fig. 2B shows possible shutdown behaviors based on the current consumption or the measured gradient of the current consumption. In particular, Fig. 2A and Fig. 2B shows the time course of the estimated value according to the invention for the deformation force or power score (P) when a blockage occurs. The power score is, in particular, a dimensionless quantity. Fig. 2A, the threshold condition is met if the estimated value exceeds the first threshold (the time of exceedance is in Fig. 2A marked by “P = P1”) or for an initial period of time (level-based overload detection). In Fig. 2B, the threshold condition is met if a temporal increase of the estimated value exceeds the second threshold (the time of the exceedance is in Fig. 2A (indicated by "dP / dt = P2") or for a second period of time (gradient-based overload detection). In both cases, the motor is shut down after the blockage to prevent subsequent damage.

[0036] The Fig. 2A and Fig. 2B can also together form the overload detection scheme used by the frequency converter (as already described in Fig. 1): Only if both detection mechanisms detect an error condition, the overload error condition is recognized and the corresponding error is set. This is also used in connection with Fig. 3 illustrates this.

[0037] Fig. Figure 3 shows an operation of a dishwasher according to an embodiment of the present invention with level and gradient-based overload detection. In particular, Fig. 3 shows the time course of the Power Score (P) when a blockage occurs. Fig. 3 parameters shown are defined as follows: - I_upper_limit: A current threshold value which, when exceeded, sets an internal error signal that the power score is critical. - I_lower_limit: If the power score was critical, the corresponding error signal is cleared when the power score falls below this threshold. This threshold is lower than I_upper_limit. - power_limit_delay: The time period during which the power score level must have been critical for the frequency converter to detect an overload condition based on the level. - dI_gradient_limit: A difference in the power score rating that, if exceeded within a timeframe of dt_gradient, will result in the detection of an overload condition based on the gradient of the power score rating. - dt_gradient: The time frame for dI_gradient_limit. A dt_gradient of zero disables gradient observation. - gradient_exceed_hold: The time period the frequency converter monitors to see if the gradient limit has been exceeded. If the gradient is exceeded again during the hold time, the monitoring period is extended.

[0038] As in Fig.As can be seen in Figure 3, after the blockage occurs, the condition dP / dt > P2 is first met ("dI_gradient_limit"). After the "dt_gradient" period, during which this condition is continuously met ("gradient_limit_exceeded"), the "gradient_exceed_hold" period begins. Within this period, the condition P > P1 is also met ("power_limit_exceeded"). After the "power_limit_delay" period, during which the latter condition is continuously met, the motor is therefore switched off ("overpower_error_detected"). The software thus shuts down the drive because a blockage has been detected based on the rapid increase in current consumption. List of reference symbols 10 Control

Claims

[1] Dishwasher, which includes: a transport device, the transport device comprising: - a transport element for moving one or more baskets for dishes along a transport direction; - a motor for driving the transport element; and - an inverter configured to convert an input voltage into an output voltage and supply the output voltage to the motor; and a current sensor configured to measure a motor current of the motor; wherein the dishwasher is configured to determine an estimated value for a deformation force of the transport device on the one or more baskets based on the motor current measured by the current sensor, a movement speed of the one or more baskets along the transport direction, a movement acceleration of the one or more baskets along the transport direction, and one or more transport device parameters; and wherein the dishwasher is configured to turn off the motor or reduce the output voltage of the inverter when a threshold condition based on one or more dishwasher parameters is met; where the threshold condition is met if: - the estimated value or the amount of the estimated value exceeds or has exceeded for a first period of time a first threshold value based on the one or more dishwasher parameters and / or - a temporal increase or an amount of a temporal increase in the estimated value or the amount of the estimated value exceeds or has exceeded for a second period of time a second threshold based on the one or more dishwasher parameters. [2] Dishwasher, which includes: a transport device, the transport device comprising: - a transport element for moving a transport belt for dishes in a circumferential direction; - a motor for driving the transport element; and - an inverter configured to convert an input voltage into an output voltage and supply the output voltage to the motor; and a current sensor configured to measure a motor current of the motor; wherein the dishwasher is configured to determine an estimated value for a deformation force of the conveyor on the conveyor belt based on the motor current measured by the current sensor, a movement speed of the conveyor belt in the direction of rotation, a movement acceleration of the conveyor belt in the direction of rotation, and one or more conveyor parameters; and wherein the dishwasher is configured to turn off the motor or reduce the output voltage of the inverter when a threshold condition based on one or more dishwasher parameters is met; where the threshold condition is met if: - the estimated value or the amount of the estimated value exceeds or has exceeded for a first period of time a first threshold value based on the one or more dishwasher parameters and / or - a temporal increase or an amount of a temporal increase in the estimated value or the amount of the estimated value exceeds or has exceeded for a second period of time a second threshold based on the one or more dishwasher parameters. [3] Dishwasher according to claim 1 or 2, further comprising a voltage determining unit for determining the input voltage of the inverter; and wherein the estimated value is further based on the input voltage of the inverter determined by the voltage determining unit. [4] Dishwasher according to one of the preceding claims, wherein the estimated value or the amount of the estimated value is greater the greater the amount of the motor current is. [5] Dishwasher according to one of the preceding claims, wherein the estimated value or the amount of the estimated value is greater the greater the input voltage is. [6] Dishwasher according to one of the preceding claims, wherein the estimated value or the amount of the estimated value is greater the greater the speed of movement of the one or more baskets along the transport direction or the transport belt in the direction of rotation. [7] Dishwasher according to one of the preceding claims, wherein the estimated value or the amount of the estimated value is smaller, the greater the acceleration of movement of the one or more baskets along the transport direction or of the transport belt in the direction of rotation. [8] Dishwasher according to one of the preceding claims, wherein the one or more dishwasher parameters comprise one or more of the following parameters: a type of dishwasher; a number of baskets or a length of the transport belt; an actual load weight or an average load weight or a maximum load weight of the dishwasher; and a period of time or a number of washing cycles of the dishwasher since the dishwasher was first put into operation. [9] Dishwasher according to claim 8, wherein the first threshold value and / or the second threshold value is greater the greater the number of baskets or the length of the conveyor belt and / or the greater the average load weight or the maximum load weight of the dishwasher. [10] Dishwasher according to claim 8 or 9, further comprising a load determining unit for determining an actual load weight of the dishwasher; wherein the first threshold value and / or the second threshold value is greater, the greater the actual load weight determined by the load determining unit is. [11] Dishwasher according to one of claims 8 to 10, which further comprises an operating time determination unit for determining a time period or a number of washing processes of the dishwasher since the dishwasher was first put into operation; wherein the first threshold value and / or the second threshold value is greater, the greater the time period or number of washing processes determined by the operating time determination unit is. [12] Dishwasher according to one of the preceding claims, wherein, when the threshold condition is met: the dishwasher is configured to switch off the motor, and the transport device is configured to move the one or more baskets back along a direction opposite to the transport direction or to move the transport belt back in a direction opposite to the direction of rotation. [13] Dishwasher according to one of the preceding claims, wherein the estimated value depends linearly on the motor current. [14] Dishwasher according to one of the preceding claims, wherein the estimated value depends linearly on the speed of movement. [15] Dishwasher according to one of the preceding claims, wherein the estimated value is based on an effective current, the effective current being a sum of the motor current and a correction current, the correction current being linearly dependent on the input voltage of the inverter. [16] Dishwasher according to claim 15, wherein the effective current (I eff ) in the following relationship to the motor current (I q ), the input voltage (U in ) of the converter, a zeroth transport device parameter (C o ) and a first transport device parameter (C1): Ieff=Iq+C0+C1*Uin. [17] Dishwasher according to claim 15 or 16, wherein the estimated value depends linearly on the effective current. [18] Dishwasher according to one of claims 15 to 17, wherein, if the movement of the one or more baskets along the transport direction or the movement of the transport belt in the direction of rotation is uniform, the estimated value is a uniformity estimated value (P uni ) which is related to the effective current (I eff ), the movement speed (v), a second transport device parameter (C2), a third transport device parameter (C3) and an eighth transport device parameter (C8): Puni=C2+C3*Ieff+C8*v; and / or where, if the movement of the one or more baskets along the transport direction or the movement of the conveyor belt in the direction of rotation is accelerated, the estimated value is an acceleration estimated value (P acc ) which is related to the effective current (I eff), the movement speed (v), a fourth transport device parameter (C4), a fifth transport device parameter (C5) and a ninth transport device parameter (C9): Pacc=C4+C5*Ieff+C9*v; and / or where, if the movement of the one or more baskets along the transport direction or the movement of the conveyor belt in the direction of rotation is delayed, the estimated value is a delay estimated value (P dec ) which is related to the effective current (I eff ), the movement speed (v), a sixth transport device parameter (C6), a seventh transport device parameter (C7) and a tenth transport device parameter (C 10 ) stands: Pdec=C6+C7*Ieff+C10*v; and / or where, if the moving speed is zero, the estimate is a standstill estimate (P still ), where the standstill estimate (P still) is zero.

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