Microwave oven

Abstract

Microwave cooking appliance (11) with a microwave distribution means (17) for coupling microwaves into a cooking chamber (12), wherein - in at least one operating mode, a height position (h) of the microwave distribution medium (17) is translationally adjustable, - the microwave cooking appliance (11) has a position adjustment device (23) which is designed to adjust the microwave distribution means (17) translationally, and - the position adjustment device (23) has at least one camshaft (26), wherein at least one cam (27) of the camshaft (26) serves as a support for a disk (28) that is freely movable relative to the camshaft (26), wherein the disk (28) is connected to the microwave distribution means (17).

Description

[0001] The invention relates to a microwave cooking appliance with a microwave distribution means for distributing microwaves into a cooking chamber.

[0002] Microwave ovens are known in which microwaves are coupled into a cooking chamber by means of a fixed microwave coupling device (e.g., an antenna with or without a wobbler). To ensure even irradiation of the food and thus its uniform heating, the food is placed on a rotating turntable. Microwave ovens without a turntable are also known, in which a microwave mode pattern inside the cooking chamber is varied by a rotating microwave distribution device (e.g., a rotating antenna or a rotating wobbler) to achieve even irradiation. Microwave ovens with a turntable also exist, in which a rotating antenna or a wobbler is incorporated to enhance this effect.

[0003] US Patent 5,182,426 A discloses a microwave antenna with three-dimensional motion. A vertical shaft carries a microwave antenna at one end and is connected at the other end to a first driven gear. A cam tappet extends from the first driven gear and engages a second driven gear with an inclined surface. The first and second driven gears are connected to each other by drive belts, ensuring independent rotation of the first and second driven gears. Either the first and second driven gears or the first and second driven gears have different diameters, so that the relative motion of the gears moves the antenna to a different rotational position after successive vertical deflections.This arrangement improves the uniformity of heating food in a microwave oven by increasing the random distribution of the mode pattern.

[0004] The object of the present invention is to design a microwave cooking appliance in such a way as to enable operation with reduced energy consumption. In particular, this should be achievable using simple means.

[0005] This problem is solved according to the features of the independent claims. Preferred embodiments can be found in particular in the dependent claims.

[0006] The problem is solved by a microwave oven with a microwave distribution device for distributing microwaves into a cooking chamber, wherein (particularly in at least one operating mode) the position of the microwave distribution device is translationally adjustable. The microwave oven has a (height) position adjustment device for this purpose, which is configured to translationally adjust at least the microwave distribution device. The position adjustment device has at least one camshaft as at least part of a lifting mechanism. At least one cam of the camshaft serves as a support for a disk that is freely movable relative to the camshaft, and the disk is connected to the microwave distribution device.

[0007] This achieves the advantage that, due to the additional degree of freedom in positioning the microwave distribution element within the cooking chamber, microwaves can form a mode pattern or interference pattern, allowing for even more efficient irradiation of the food being cooked. In particular, the translational adjustment is not a purely rotational movement. Specifically, this allows for a greater intensity of microwave radiation to be applied to regions where the food is located. This is especially true for food that is spatially limited in size. This principle utilizes the fact that microwaves overlap particularly strongly in certain regions at specific positions of the microwave distribution element due to interference. These overlaps arise, among other things, because the reflection pattern of the microwaves at the walls of the cooking chamber changes depending on the rotational position and height of the microwave distribution element. By adjusting the height position or height, the microwave distribution pattern can be optimized.By translationally adjusting the microwave distribution element to a load in the cooking chamber, the efficiency of the microwave function can be improved. This allows for increased efficiency and / or reduced energy consumption while achieving the same cooking result. Furthermore, certain foods or liquids can be heated more quickly.

[0008] The invention can be used for microwave cooking appliances with a rotatable microwave distribution means as well as for microwave cooking appliances with a non-rotatable microwave distribution means.

[0009] In particular, a translational adjustment can include movement towards the cooking chamber, i.e., forwards or backwards. In other words, during operation in this at least one operating mode, the microwave distribution element is adjusted relative to the cooking chamber or relative to the food being cooked therein, in particular raised and / or lowered. If the microwave distribution element is located above the cooking chamber, the translational adjustment corresponds in particular to a vertical adjustment of the microwave distribution element. If the microwave distribution element is located to the side of the cooking chamber, the translational adjustment corresponds in particular to a horizontal adjustment of the microwave distribution element.The translational displacement is generally referred to as a "height adjustment" in the following, even if the microwave distribution element is located laterally within the cooking chamber and is horizontally movable. Accordingly, a translational position achieved through the translational adjustment can also be referred to as a height position.

[0010] Such a microwave cooking appliance can be designed in particular as a stand-alone unit or as a combination unit, e.g. a microwave oven / oven combination.

[0011] To couple microwaves into the cooking chamber, a non-rotating or a rotating antenna may be used. The microwave distribution element for a non-rotating antenna may be a wobbler. The microwave distribution element for a rotating antenna may be the antenna itself. The antenna may have a tubular microwave feed line. If the antenna is rotatable, the tubular microwave feed line may be connected to the axis of rotation. A wobbler, on the other hand, typically has a separate axis of rotation from the microwave feed line.

[0012] According to one advanced training, rotation of the microwave distribution element and / or a turntable may be unnecessary, particularly for small-volume food items (baby food jars, glasses of water, etc.). However, another advanced training suggests that both translational displacement or height adjustment of the microwave distribution element and rotation of the microwave distribution element and / or a turntable can be used to cook food, especially simultaneously.

[0013] The position adjustment device may in particular include an adjustment drive (actuating device), especially a (lifting) actuator or a (lifting) motor.

[0014] According to a further development, the position adjustment device is located inside the housing, but in particular to avoid contamination by evaporating or splashing food particles, it is located outside the cooking chamber.

[0015] The lifting actuator can be designed, for example, to easily effect a linear positioning movement between two or more predetermined positions. The lifting actuator also enables high adjustment force and very precise stroke changes, thus allowing translational adjustability of the microwave distribution medium.

[0016] The lifting motor can be designed, for example, as a servo or stepper motor, or as a BLDC motor (BLDC: Brushless DC Motor). A rotatable microwave distribution unit can also have a rotary drive motor in the form of a BLDC motor. Stepper motors are particularly advantageous, as they allow for targeted movement to specific height positions or height ranges via a linear encoder. However, other types of drive motors can also be used, especially in conjunction with a position detection device that reports the instantaneous height position of the microwave distribution unit (e.g., to a control unit).

[0017] The position adjustment device may further comprise a lifting mechanism which is connected downstream of the adjustment drive or which can be actuated by it. The lifting mechanism may, for example, comprise a lifting and / or rotary linkage. The lifting mechanism may, in particular, effect a change in the direction of a lifting input and / or a lifting transmission. Specifically, the lifting mechanism may convert a rotary movement of the adjustment drive into a linear lifting movement.

[0018] In a further development process where the microwave distribution element is raised translationally by means of the adjustment drive, resetting or lowering can be achieved, if necessary, by utilizing gravity and removing an actuating force from the adjustment drive. Particularly in the case of translational lateral adjustment (especially with a horizontal or lateral arrangement of the microwave distribution element), an additional actuating or motor force, i.e., a force acting in the opposite direction, can be applied to the microwave distribution element for resetting.

[0019] The use of a camshaft allows for versatile stroke adjustment, a high stroke ratio, and a robust and simple design of the stroke mechanism. A rotational position of the camshaft corresponds to a corresponding vertical position. By rotating the camshaft, the disc can be raised or lowered. If the microwave distribution element is rotatable, the disc (which can also be called a plate) can rotate freely on the camshaft, independent of the camshaft's rotational position. The camshaft can, in particular, have two or more camshafts to reduce torque on the disc.

[0020] It is a further development that the disk is rigidly connected to a rotational axis of the rotatable microwave distribution element (i.e., the antenna or wobbler). Consequently, the microwave distribution element, the rotational axis, and the disk can perform a rotational movement relative to the camshaft and the position adjustment device. In particular, the rotational axis of the disk thus also corresponds to a translational axis of the microwave distribution element.

[0021] In a further embodiment, the microwave distribution element has a translationally adjustable axis of rotation. This axis of rotation can be set in motion, for example, by means of a rotary drive, in particular a drive motor, especially a BDLC motor. In other words, in this embodiment, the microwave distribution element can be set in rotation about its axis of rotation and also adjusted translationally (in height) in its axial direction. The setting of the microwave distribution element in rotation and its translational adjustment can, in particular, be carried out independently of each other.

[0022] It is a further development that a rotary axis that is simultaneously translationally adjustable does not constitute a motor shaft of a drive motor for a rotary movement of the rotary axis.

[0023] This prevents translational movement from damaging the (rotary) drive motor.

[0024] This configuration involves the rotary axis and the antenna being mechanically coupled, with the rotary axis and a rotary drive rotating the axis being mechanically coupled by means of a drive mechanism. This allows the rotary axis to be translationally decoupled from the rotary motor.

[0025] According to a particularly simple embodiment, a drive mechanism can be articulated on one side to a motor shaft of the (rotary) drive motor and on the other side to engage the axis of rotation of the microwave distribution device. In particular, the drive mechanism can have an element that is laterally offset from the axis of rotation or the motor shaft, especially a projecting, axially parallel element, and the motor shaft or the axis of rotation can have a laterally projecting projection which is driven along by the axially parallel element when it rotates. For example, a pin or projection may project laterally from the axis of rotation as a first drive element of a drive mechanism.A second drive element may be connected to the rotary drive, wherein the second drive element is arranged in particular parallel to the axis and is rotatable on a circular path around the axis and, upon rotation, comes into contact with the first drive element and thereby sets the axis in rotation.

[0026] However, the drive mechanism can also be designed differently, or the axis of rotation may be coupled to the motor shaft in a different way. For example, the axis of rotation may have a toothed outer circumference that engages with a worm gear of the rotary drive, or vice versa.

[0027] It is also a feature that the (height) position of the microwave distribution element (in at least one operating mode) is adjustable within a predetermined position range. In other words, the microwave distribution element can be raised and / or lowered, or moved back and forth, between two predetermined height positions by means of the position adjustment device. Accordingly, a field maximum or a number of field maxima move within the cooking chamber in a predetermined spatial area. This translational back-and-forth movement thus particularly supports the movement of at least one field maximum within the food being cooked, and therefore its uniform heating, especially in the case of food with low thermal conductivity. In particular, at least one field maximum can thus be located inside, for example, a [missing information - likely a specific container or dish].The movement of small food items allows a particularly high proportion of the available energy to be concentrated there, thus supporting energy-efficient heating. The position range can depend on the design and dimensions of the appliance and its cooking chamber, the radiation range of the microwave distribution element, and / or the type of food being cooked or its weight, etc. The movement and its limitations can be achieved, for example, through electronic control or mechanical means.

[0028] Another embodiment involves making the position of the microwave distribution element (in at least one operating mode) adjustable to at least one fixed, predetermined position. In this case, a field maximum can remain permanently in a small-volume and / or highly thermally conductive food item and transfer its energy there.

[0029] According to further training, several fixed predetermined positions can also be provided, which are approached successively during operation in one operating mode, e.g. depending on the type of food to be treated and / or the weight of the food being cooked, and in which the microwave distribution medium remains for a period of time, which may also be individually predetermined.

[0030] Furthermore, one embodiment of the microwave oven is configured to select an operating mode and / or the translational adjustment or height position of the microwave distribution element (in particular its antenna or wobbler) based on the type of food being cooked in the cooking chamber. This allows for consistent heating of even different types of food. For example, thermally conductive food (e.g., soup) may be irradiated with a predetermined adjustment range (e.g., with a continuous or oscillating movement between two positions), possibly also at a fixed, predetermined height position, while thermally less conductive food requires a larger translational adjustment range or a different height position. The typical shape of the food may also play a role: While pizza is usually flat and fills the space and therefore may require interference maxima near the bottom, for example,A baby bottle or a roast can be heated better in the oven using higher interference maxima.

[0031] In particular, such a selection can be made automatically after a user has specified or set the type of food to be heated, for example pizza, baby bottle or roast.

[0032] According to further training, the intensity or strength of the microwaves can also be modified. In particular, such a process can also run automatically after a user has specified a particular item to cook, such as pizza, a baby bottle, or a roast. While a pizza is usually flat and fills the entire space, making continuous rotation, possibly without adjusting its position in a standard position, practical, a baby bottle or a roast tends to cover only a central area in the cooking chamber, so adjusting the height position can be particularly advantageous in these cases.

[0033] An additional or alternative development involves the microwave oven being configured to select the operating mode and / or the translational adjustment or height position of the microwave distribution element based on the weight of the food being cooked in the cooking chamber. This allows the translational setting (range, position) of the microwave distribution element to be adjusted according to a parameter typically correlated with weight, resulting in further improved, consistent heating with lower energy consumption.

[0034] In particular, the operating mode and the translational setting of the microwave distribution system can be adjusted based on both the type and weight of the food being cooked. For example, 2 liters of thick soup will likely occupy a large portion of the cooking chamber, making an oscillating translational movement appropriate, whereas a 200 ml baby bottle will likely occupy a central position in the cooking chamber, making a fixed height position more suitable.

[0035] A general design feature of the microwave oven is an automatic program function that selects the operating mode and / or the translational setting of the microwave distribution element based on a chosen program. This function can utilize empirical data or values ​​for the operating mode and / or rotation angle range determined through calculations or experiments. For example, if a user enters a type of food and a specific weight, the automatic program function can decide whether and which translational adjustment to select.

[0036] One further development consists of the microwave oven having an input device. According to this further development, the input device may comprise a control panel with at least one operating element and, optionally, at least one display device. The input device may be designed, in particular, for a user to enter a specific food to be cooked and / or its weight, or to enter a desired program.

[0037] Another further development involves the microwave oven having at least one position detection device. A position detection device is advantageous because it allows for the unambiguous determination of a specific target height range or position. This ensures that the microwave distribution element is either in a desired height position or is moved back and forth within a desired height range.

[0038] The microwave oven has, in particular, a control unit for controlling the operation of the microwave oven itself, including its magnetron, its adjustment drive for translational position adjustment, and optionally its motor or drive for a turntable and / or the microwave distribution element to set these in rotation. In particular, such a control unit is also coupled with a position determination device to determine a defined height position of the microwave distribution element. However, other procedures may also be provided, such as moving the microwave distribution element to a home position, which then provides a defined base value for the current height position, in order to subsequently control specific height positions or height position ranges from this position value.

[0039] The microwave oven may be a household appliance, especially for a private user, e.g. in the sense of a "white goods".

[0040] The following figures describe the invention in more detail schematically using an exemplary embodiment. Fig. Figure 1 shows a section of a microwave oven with a cooking chamber and a microwave distribution device; and Fig. Figure 2 shows an excerpt from Fig. 1 with an antenna mounting and a position adjustment device for translational adjustment of the antenna.

[0041] Fig. Figure 1 shows a section of a microwave oven 11. The microwave oven 11 has a cooking chamber 12 and an operating chamber 13 separated from it, for example, by a metal wall. The operating chamber 13 contains, in particular, components of a microwave unit 14, which serves to generate microwaves that are fed into the cooking chamber 12 through an opening. The cooking chamber 12 serves to hold a container 15 with food 16, which is to be defrosted, warmed, or heated, for example.

[0042] The microwave device 14 includes, in particular, a microwave distribution element 17, which, for example, acts as an antenna 18 and directs microwaves into the cooking chamber 12. The antenna 18, or the microwave distribution element 17, is coupled to a magnetron 20 via a waveguide 19 in order to direct microwaves generated in the magnetron 20 into the cooking chamber 12 via the waveguide 19 and the antenna 18.

[0043] The antenna 18 is coupled to a drive motor 22 via a rotatable axis 21. The drive motor 22 sets the axis 21 and the antenna 18 attached to it into a rotation ω, in particular a continuous rotation.

[0044] The microwave oven 11 also has a position adjustment device 23 which, in at least one operating mode, is designed to adjust the vertical position h of the axis of rotation 21 or the antenna 18 translationally. In other words, the antenna 18 is moved back and forth along the axis of rotation 21. If this changes the level or vertical position h of the antenna 18 or of a wobbler in the cooking chamber or waveguide, then the mode pattern or field distribution, as well as the tuning of the overall system, are also changed.

[0045] How Fig.As shown in the enlarged view in Figure 2, the position adjustment device 23 has an adjustment drive 24. The adjustment drive 24 is fixedly arranged within the operating chamber 13 and / or relative to the waveguide 19. The adjustment drive 24 has a camshaft 26, which rotates by an angle α to adjust the height position. The camshaft 26 has at least one cam 27, which extends unevenly around a circumference of the camshaft 26 and acts like a lever. Furthermore, the axis of rotation 21 has a disk 28 extending radially around the circumference. The disk 28 rests on the camshaft 26 in the area of ​​its cam 27. Rotation of the camshaft 26 thus causes the disk 28 to be raised via the cam 27 or lowered again by gravity.In this configuration, the maximum amount of change in the height position h of the axis of rotation 21 corresponds to a distance between the smallest circumference of the camshaft 26 and the maximum elevation of the cam 27 from this circumference.

[0046] The cams 27 are specifically rounded, i.e., not angular, to allow for smooth adjustment of the disc 28. The disc 28 is designed with a flat underside to serve as a sliding surface for sliding on the cams 27.

[0047] To enable rotation of the axis of rotation 21, a shaft extends from the drive motor 22, initially following an angled path and then becoming parallel to the axis of rotation 21. The section running parallel to the axis of rotation 21 by an offset v forms a rotary drive element 29. The axis of rotation 21 has a laterally projecting driver 30 in its upper region. When the drive motor 22 sets the rotary drive element 29 in rotation about the axis of rotation 21, the rotary drive element 29, via the driver 30, engages the axis of rotation 21 and thereby also sets the axis of rotation ω in motion. Due to the sliding connection between the rotary drive element 29 and the driver 30, which is loose in the axial direction of the axis of rotation 21, the axis of rotation 21 can simultaneously be adjusted translationally along its axis of rotation by means of the position adjustment device 23.

[0048] A control unit 25 serves to control functions of the microwave cooking appliance 11. These include, in particular, the operation of the magnetron 20 for generating microwaves and the control of the drive motor 22 and the position adjustment device 23. The control of the drive motor 22 can be effected, in particular, such that the microwave distribution element 17 is continuously and / or successively moved to a predetermined height position h within the adjustable (height) position range, according to at least one operating mode. The control unit 25 can also, in particular in conjunction with an input field (not shown), serve to record certain user inputs, such as the type of food to be cooked and / or its weight, in order to make pre-programmed adjustments to the height position h accordingly.

[0049] Of course, the present invention is not limited to the embodiment shown.

[0050] In the described design, the antenna's axis of rotation and its disc are made from a single piece. Alternatively, an additional disc can be permanently mounted to the axis, which is, for example, a ceramic shaft.

[0051] However, there are other possibilities for the constructive implementation. For example, a solution using an adjustment drive as a linear actuator is feasible. This actuator is integrated into an axis with the microwave distribution element, i.e., in particular the antenna system / wobbler, and can change the height or position of the entire antenna system.

[0052] Generally, a microwave oven with a fixed antenna and a height-adjustable wobbler can also be used.

[0053] In a microwave oven with a turntable for rotating the food, the drive motor and the components for rotating the axis can be omitted. Particularly in such a case, the adjustment drive can be designed as a linear drive, which may even directly adjust the axis's height position.

[0054] In particular, other types of drivers, e.g. spring-groove guides, can also be arranged between the adjusting drive and the axle for height position adjustment.

[0055] Particularly in the case of a lateral adjustment device for the "height" position, the return to the starting position can also be achieved via drive elements or guide elements due to the lack of usable gravity.

[0056] After activating a microwave operating mode, the system may automatically move to a pre-programmed height position of the antenna / wobbler stored in a control unit or electronics. In the finished device, depending on the specific configuration, the user may only need to select the power output, or the power output and weight of the food being cooked. The control unit then positions the antenna or wobbler relative to the cooking chamber and the food inside, according to the selected height position. If the antenna or wobbler is mounted laterally, its height position (h) within the cooking chamber / waveguide is adjusted horizontally. It is also possible to configure the system to continuously adjust the antenna system's position during microwave operation to achieve optimal cooking results.

[0057] An optional additional tuning option allows the magnetron to be operated at maximum power only in desired operating modes, such as heating liquids. This is not strictly necessary for many other applications. This helps prevent potential magnetron damage.

[0058] For example, a position determination device can be provided with which the current height position h of the antenna 18 can be determined. Such a function can also be achieved by using a stepper motor for the adjustment drive, the stepwise control of which allows a conclusion to be drawn about the current height position h.

[0059] Instead of or in addition to user input via an input field, sensors can also be provided that enable automatic determination of the conditions in the cooking chamber. For example, it can be provided that the type of food being cooked and / or its volume or weight is automatically determined in order to select at least a suitable operating program or mode.

[0060] In particular, the operating mode can also take into account empirical data or values ​​determined during a development phase. For example, water loads or volumes of varying sizes can be heated at different fixed antenna or wobbler angle positions. From this, it can be determined which height position is optimal for which water load. It is also conceivable to determine a common height position at which, on average, all water loads are heated effectively. Furthermore, a mathematical calculation of field maxima, depending on, for example, the geometry and size of the cooking chamber or the microwave distribution medium, can be used to determine such control values.

[0061] In particular, a suitable program control system enables the user of the finished microwave oven to select, depending on the specific solution, only the power level or the power level and weight of the food being cooked. The control unit then moves or positions the microwave distribution element accordingly within a predetermined range or at fixed, predetermined height positions. Reference symbol list 11 Cooking appliance 12 Oven space 13 Operating room 14 Microwave oven 15 containers 16 items cooked 17 Microwave distribution devices 18 Antenna 19 waveguides 20 Magnetron 21 axis of rotation 22 Drive motor 23 Position adjustment device 24 Adjustment drive, in particular lifting actuator or lifting motor 25 Control unit 26 Camshaft 27 cams 28 disc 29 Rotary drive element 30 drive lugs on axle h translationally adjustable height position v offset z axis of rotation α Rotation angle for position adjustment ω Rotation or rotation of the axis

Claims

Microwave cooking appliance (11) with a microwave distribution means (17) for coupling microwaves into a cooking chamber (12), wherein - in at least one operating mode a height position (h) of the microwave distribution means (17) is translationally adjustable, - the microwave cooking appliance (11) has a position adjustment device (23) which is configured to translationally adjust the microwave distribution means (17), and - the position adjustment device (23) has at least one camshaft (26), wherein at least one cam (27) of the camshaft (26) serves as a support for a disk (28) that is freely movable relative to the camshaft (26), wherein the disk (28) is connected to the microwave distribution means (17). Microwave cooking appliance (11) according to claim 1, characterized in that the microwave distribution means (17) has a translationally adjustable rotary axis (21). Microwave cooking appliance (11) according to claim 2, characterized in that the microwave cooking appliance (11) has an antenna (18), wherein the axis of rotation (21) and the antenna (18) are coupled together, wherein the axis of rotation (21) and a rotary drive rotating the axis of rotation (21) are coupled by means of a drive arrangement (29, 30). Microwave cooking appliance (11) according to one of the preceding claims, characterized in that the height position (h) of the microwave distribution means (17) is adjustable in a predetermined position range. Microwave cooking appliance (11) according to one of the preceding claims, characterized in that the height position (h) of the microwave distribution means (17) is adjustable to at least one fixed predetermined height position (h). Microwave cooking appliance (11) according to claim 5, characterized in that the height position (h) of the microwave distribution means (17) can be adjusted to exactly one fixed predetermined height position (h) during operation in at least one operating mode. Microwave oven (11) according to one of claims 5 to 6, characterized in that the height position (h) of the microwave distribution means (17) can be adjusted to several fixed predetermined height positions (h) during operation in at least one operating mode, which are approached successively in one operating mode and in which the microwave distribution means (17) remains for a predetermined period of time. Microwave cooking appliance (11) according to one of the preceding claims, including claims 4 and 5, characterized in that the microwave cooking appliance (11) is configured to select the predetermined position range and / or the predetermined height position (h) based on the type of food (16) located in the cooking chamber (12). Microwave cooking appliance (11) according to one of the preceding claims, characterized in that the microwave cooking appliance (11) is configured to select the operating mode and / or the translational adjustment based on the weight of a food (16) located in the cooking chamber (12). Microwave oven (11) according to one of the preceding claims, characterized in that the microwave oven (11) has an automatic program function which is configured to select, on the basis of a selected program, whether and which translational adjustment is selected. Microwave cooking appliance (11) according to one of the preceding claims, but not in conjunction with claim 3, characterized in that the microwave distribution means (17) has an antenna (18) or a wobbler.

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