Cooking appliance comprising a cooking chamber and a fan for circulating cooking chamber air, and method for its operation

Description

[0001] The invention relates to a cooking appliance comprising a cooking chamber and a blower for circulating cooking chamber air of the type mentioned in the preamble of claim 1, as well as a method for its operation.

[0002] Such cooking appliances and methods for their operation are known in the prior art in a multitude of embodiments. For example, publication JP 2006 283 584 A discloses a cooking appliance of this type.

[0003] Generally, cooking appliances comprise a housing, a cooking chamber arranged in the housing and bounded by the walls of the housing, a cooking chamber door for closing an opening of the cooking chamber in a closed position, at least one heater for heating the cooking chamber, a fan for circulating cooking chamber air, wherein a fan wheel of the fan is located in the cooking chamber and a motor of the fan is located outside the cooking chamber on the housing, and wherein the fan wheel is connected to the motor by means of a drive shaft passing through a drive shaft opening in one of the walls of the cooking chamber, transmitting torque, and a control unit for controlling the heater and the fan. Such cooking appliances are known, for example, from the publications DE 10 2016 115 529 A1, DE 10 2015 109 854 A1, US 5 526 734 A, DE 24 60 294 A1, EP 3 838 086 A1 and FR 2 396 244 A1.

[0004] The invention thus addresses the problem of improving a cooking appliance comprising a cooking chamber and a blower for circulating cooking chamber air, and a method for its operation.

[0005] According to the invention, this problem is solved by a cooking appliance with the features of claim 1. The cooking appliance according to the invention can be, for example, an oven, a microwave oven, a steam cooker, or a combination appliance with a plurality of different heating methods. The cooking appliance according to the invention can also be designed as a household appliance or as a commercial appliance, i.e., a cooking appliance for professional use. Furthermore, this problem is solved by a method with the features of claim 10. Advantageous embodiments and further developments of the invention are described in the dependent claims.

[0006] The advantage achievable with the invention lies particularly in the fact that a cooking appliance, comprising a cooking chamber and a fan for circulating cooking chamber air, and a method for its operation are improved. Due to the inventive design of the cooking appliance and the method, namely by the different positioning of the fan wheel of the blower in the cooking chamber axially to the drive shaft, the airflow through the cooking chamber can be adjusted, and thus the cooking process taking place in the cooking chamber of the cooking appliance according to the invention can be influenced as desired. Accordingly, the heat distribution in the cooking chamber, and thus the cooking result of a cooking process taking place in the cooking chamber of the cooking appliance according to the invention, can be influenced much more effectively.Thus, the cooking process can be controlled or regulated not only by means of the speed of the blower to circulate the cooking chamber air, but also by the position of the fan wheel in the cooking chamber axially to the drive shaft, for example behind a rear wall inserted into the cooking chamber.

[0007] In principle, the cooking device according to the invention can be freely selected within wide suitable limits with regard to type, function, material and dimensions. See also the above explanations in the introductory description.

[0008] A particularly advantageous embodiment of the cooking appliance according to the invention provides that the shifting device is designed such that, depending on an operating state of the cooking appliance and / or a cooking program selected on the cooking appliance and / or a cooking process in the cooking chamber, the fan wheel can be automatically positioned by means of the shifting device at least in an intermediate position of the fan wheel between the first end position and the second end position. In this way, the adjustability of the position of the fan wheel axially to the drive shaft is further improved, so that the circulation of the cooking chamber air can be designed even more variably.

[0009] Accordingly, an advantageous further development of the method according to the invention provides that the shifting device automatically positions the fan wheel in the cooking chamber at least in an intermediate position of the fan wheel between the first end position and the second end position, depending on an operating state of the cooking appliance and / or a cooking program selected on the cooking appliance and / or a cooking process.

[0010] A further advantageous embodiment of the cooking device according to the invention provides that the cooking device has at least one sensor connected to the control unit via signal transmission for the automatic detection of at least one cooking parameter of the cooking process. Preferably, the at least one sensor is designed as a cooking chamber camera for observing food located in the cooking chamber and / or a humidity sensor for determining the humidity prevailing in the cooking chamber and / or a temperature sensor for determining the cooking chamber temperature and / or the temperature of food located in the cooking chamber. This allows for a particularly effective positioning of the fan wheel axially to the drive shaft depending on the cooking process taking place in the cooking chamber of the cooking device according to the invention.By means of at least one sensor for automatically detecting at least one cooking parameter of the cooking process, the position of the fan wheel of the blower, axially relative to the drive shaft, can be adjusted to suit the requirements of each individual case. This applies in particular to the preferred embodiment of this further development. The cooking chamber camera can be designed to detect visible light and / or infrared radiation.

[0011] Accordingly, an advantageous further development of the method according to the invention provides that the cooking device has at least one sensor connected to the control system via signal transmission, by means of which at least one cooking parameter of the cooking process is automatically detected, preferably that the at least one sensor is used to observe food located in the cooking chamber using a camera-based method and / or to determine the humidity prevailing in the cooking chamber and / or to determine the cooking chamber temperature and / or the temperature of food located in the cooking chamber.

[0012] Another advantageous embodiment of the cooking device according to the invention provides that the shifting device includes the motor, wherein the motor is designed as a shaded-pole motor such that the drive shaft, which is connected to a rotor of the shaded-pole motor in a torque-transmitting manner, automatically moves and positions the fan wheel in its first end position or its second end position, preferably in its first end position, in at least one intermediate position, or in its second end position, depending on the control signal from a plurality of coils of a stator of the shaded-pole motor by means of the rotor mounted in the stator. In this way, the shifting device can be implemented in a particularly simple manner in terms of design, manufacturing, and circuitry, and in a very space-saving manner.

[0013] An advantageous embodiment of the aforementioned embodiment of the cooking device according to the invention provides that the majority of the coils are configured as a first coil and a second coil separated from the first coil by means of an electrical insulator. The first coil, the second coil, and the control circuit are configured such that the first coil and the second coil can be electrically connected to each other in a series circuit and / or a parallel circuit by means of the control circuit. This allows for a particularly simple circuit-based positioning of the fan wheel axially to the drive shaft. This applies especially to the design of the displacement device, by means of which the fan wheel can be automatically positioned not only in its first and second end positions, but also in at least one intermediate position between the first and second end positions.

[0014] According to the invention, the cooking device is provided in such a way that a cone is formed and arranged on the drive shaft and a cone-shaped boundary surface corresponding to the cone is formed and arranged on the cooking chamber wall that limits the drive shaft opening, such that the cone and the boundary surface form an annular gap for supplying fresh air from a free environment into the cooking chamber, wherein a clear cross-section of the annular gap has a predetermined minimum passage area in the first end position of the fan wheel and a predetermined maximum passage area in the second end position of the fan wheel.In this way, the amount of fresh air drawn in from the surrounding environment by the fan through the annular gap is adjustable, thus allowing the heat distribution in the cooking chamber to be controlled or regulated essentially independently of the fan speed, depending on the operating state of the cooking appliance and / or a cooking program selected on the cooking appliance and / or a cooking process in the cooking chamber. The positioning of the fan wheel in the aforementioned range between the first and second end positions axially to the drive shaft can be stepless, i.e., continuous, or in stages. This provides a further possibility of influencing a cooking process and thus the cooking result of a cooking process taking place in the cooking chamber of the cooking appliance according to the invention.In combination with different fan speeds for circulating the cooking chamber air and / or with controlled or regulated steam extraction from the cooking chamber, additional possibilities arise for varying the rinsing of the cooking chamber of the cooking appliance according to the invention during an ongoing cooking process.

[0015] An advantageous further development of the aforementioned embodiment of the cooking device according to the invention, referring back to claim 2, provides that the clear cross-section of the annular gap in the at least one intermediate position of the fan wheel has a passage area whose size lies between the minimum and the maximum passage area. The area of ​​the clear cross-section of the annular gap in the at least one intermediate position of the fan wheel is therefore larger than the passage area of ​​the clear cross-section of the annular gap corresponding to the first end position of the fan wheel and smaller than the passage area of ​​the clear cross-section of the annular gap corresponding to the second end position of the fan wheel. This allows for a finely graduated supply of fresh air from the surrounding environment via the annular gap.As explained above, the axial displacement of the fan wheel relative to the drive shaft can be carried out continuously, i.e. steadily, or in steps using the displacement device.

[0016] An advantageous further development of the two latter embodiments of the cooking device according to the invention provides that the sliding device has a motor mount for the motor, which is movably held on the housing, and a motor mount drive connected to the motor mount in a force-transmitting manner, wherein the motor mount is movable axially relative to the drive shaft depending on the control signal of the motor mount drive by means of the control unit. In this way, the sliding device can be implemented in a structurally and manufacturably simple manner.

[0017] An advantageous embodiment of the cooking device according to claim 8 provides that the motor mount has a mounting plate movably held on the housing by means of a longitudinal guide device of the cooking device for the motor mount; preferably, that the longitudinal guide device has a plurality of guide pins and corresponding guide openings; particularly preferably, that the guide pins are arranged on the housing and the guide openings are arranged or formed on the mounting plate. This allows the motor mount of the sliding device to be implemented in a structurally and manufacturably robust manner. This applies particularly to the preferred and especially to the particularly preferred embodiment of this embodiment.

[0018] An advantageous embodiment of the cooking device according to claim 8 or 9 provides that the motor mounting drive, which can be controlled by the control unit, has a spur gear and the mounting plate has a rack that corresponds to and engages with the spur gear. In this way, the power transmission connection between the motor mounting drive on the one hand and the motor mounting on the other hand is implemented in a very robust and reliable manner.

[0019] Two embodiments of the invention are shown schematically in the drawings and are described in more detail below. It shows Figure 1 shows a first - unclaimed - embodiment of a cooking appliance in a partial, cutaway side view; Figure 2 shows the blower of the first embodiment in an enlarged, perspective detail view; Figure 3 shows the blower made of Fig. 2 in a first cutaway side view, with the fan wheel in its first end position, Figure 3b the blower made of Fig. 2 in a second cutaway side view, with the fan wheel in its second end position, Figure 3c the blower made of Fig. 2 Figure 4 shows a second embodiment of the cooking device according to the invention for carrying out the method according to the invention in a partial, sectional side view, Figure 5 shows the second embodiment in a rear, perspective detail view in the area of ​​the motor of the blower, Figure 6 shows the second embodiment in a first partial, sectional side view in the area of ​​the blower, with the fan wheel in its first end position, Figure 6b shows the second embodiment in a second partial, sectional side view in the area of ​​the blower, with the fan wheel in its intermediate position, and Figure 6c shows the second embodiment in a third partial, sectional side view in the area of ​​the blower, with the fan wheel in its second end position.

[0020] In the Fig. 1 bis 3c A first embodiment of an unclaimed cooking device is shown purely as an example.

[0021] The cooking appliance 2 is designed as a household oven and comprises a housing 4, a cooking chamber 8 arranged in the housing 4 and bounded by cooking chamber walls 6 of the housing 4, a cooking chamber door (not shown) for closing a cooking chamber opening 10 of the cooking chamber 8 in a closed position of the cooking chamber door, at least one heating element (also not shown) for heating the cooking chamber 8, a fan 12 for circulating cooking chamber air located in the cooking chamber 8, wherein a fan wheel 14 of the fan 12 is arranged in the cooking chamber 8 and a motor 16 of the fan 12 is arranged on the housing 4 outside the cooking chamber 8, and wherein the fan wheel 14 is connected to the motor 16 by means of a drive shaft 20 passing through a drive shaft opening 18 in one of the cooking chamber walls 6, transmitting torque, and a control unit (not shown) for controlling the heating element and the fan 12.In the present embodiment, the fan wheel 14 of the blower 12 is arranged behind a rear wall 22 inserted into the cooking chamber 8, with openings for the circulated cooking chamber air. The cooking chamber air circulated in the cooking chamber 8 is in the . Fig. 1 bis 3c also not shown. As is usual in the prior art, it is also the case here that during a cooking process taking place in the cooking chamber, steam, and thus a part of the cooking chamber air, can be released from the cooking chamber 8 into the free environment in a manner known to those skilled in the art.

[0022] According to the invention, the fan wheel 14 is moved between a position in the cooking chamber 8 by means of a shifting device 24 of the cooking appliance 2, which is connected to the control unit via a signal transmission, depending on an operating state of the cooking appliance 2 and / or a cooking program selected on the cooking appliance 2 and / or a cooking process in the cooking chamber 8. Fig. 3a depicted first end position and one in the Fig. 1 and 3bThe second end position of the fan wheel 14, as shown, can be automatically displaced axially relative to the drive shaft 20 and positioned in the respective end position. The displacement device 24 is further designed such that, depending on an operating state of the cooking appliance 2 and / or a cooking program selected on the cooking appliance 2 and / or a cooking process in the cooking chamber 8, the fan wheel 14 can be moved by means of the displacement device 24 into a position shown in the Fig. 3c The intermediate position of the fan wheel 14 between the first and second end positions is shown and can be automatically positioned. For the purpose of moving the fan wheel 14 by means of the moving device 24 depending on a cooking process taking place in the cooking chamber 8, the cooking appliance 2 can have at least one sensor connected to the control unit for signal transmission and for automatically detecting at least one cooking parameter of the cooking process. The at least one sensor is located in the Fig. 1 bis 3c The food being cooked is not shown. Preferably, the at least one sensor is configured as a cooking chamber camera for observing food located in the cooking chamber 8 and / or a humidity sensor for determining the humidity in the cooking chamber 8 and / or a temperature sensor for determining the cooking chamber temperature in the cooking chamber 8 and / or the temperature of food located in the cooking chamber 8. The food being cooked is also not shown.

[0023] In the present first embodiment, the displacement device 24 comprises the motor 16, wherein the motor 16 is designed as a shaded-pole motor such that the drive shaft 20, which is connected to a rotor 26 of the shaded-pole motor 16 in a torque-transmitting manner, automatically moves and positions the fan wheel 14 in its first end position, in its at least one intermediate position, or in its second end position, depending on the control by a plurality of coils 28, 30 of a stator 32 of the shaded-pole motor 16 by means of the rotor 26 mounted in the stator 32.In the present embodiment, the majority of the coils 28, 30 are configured as a first coil 28 and a second coil 30 separated from the first coil 28 by means of an electrical insulator 34, wherein the first coil 28 and the second coil 30, as well as the control unit, are configured such that the first coil 28 and the second coil 30 can be electrically connected to each other in a series circuit and / or a parallel circuit by means of the control unit. See the [reference to be added]. Fig. 3a bis 3c In summary, the coils 28 and 30 can, for example, be configured as so-called coil packs. Furthermore, it is conceivable that the coils 28 and 30 are designed differently from one another, so that different rotational speeds can be achieved with the coils 28 and 30 in the motor 16. Accordingly, the rotor 26 of the motor 16 would, with the fan wheel 14 in its first end position, according to the Fig. 3a with a first rotational speed and with the fan wheel 14 in the second end position according to the Fig. 3b with a second speed different from the first speed. Furthermore, by means of the aforementioned series and parallel connection of the two coils 28, 30, two additional speeds of the rotor 26 of the motor 16, and thus of the drive shaft 20 connected to the rotor 26 in a torque-transmitting manner, can be realized, whereby the fan wheel 14 rotates in the Fig. 3c The intermediate layer shown is located there.

[0024] The following describes the functioning of the cooking device according to the invention and the method according to the invention in the first embodiment with reference to the Fig. 1 bis 3c explained in more detail.

[0025] The food to be cooked (not shown) has been placed in the cooking chamber 8 of the cooking appliance 2, and the cooking chamber door (also not shown) has been closed. A user (not shown) selects a cooking program for preparing the food on the cooking appliance 2 in a manner known to those skilled in the art and starts this cooking program, thus initiating the cooking process. During the cooking process taking place in the cooking chamber 8, the fan wheel 14 is automatically moved axially to the drive shaft 20 by means of the sliding device 24 between the first end position, the intermediate position, and the second end position of the fan wheel 14, depending on the cooking program selected on the cooking appliance 2 and the cooking process taking place in the cooking chamber 8, namely depending on at least one cooking parameter determined by means of the at least one sensor (not shown), and positioned in the first end position, the intermediate position, or the second end position.For this purpose, the motor 16, namely the stator 32 of the motor 16, is controlled accordingly by the control unit of the cooking appliance 2 during the cooking process taking place in the cooking chamber 8. For example, the rotor 26 is moved axially to the drive shaft 20 in the . Fig. 3a The rotor 26 is pulled into the position shown, corresponding to the first end position of the fan wheel 14, when the coil 28 is energized. If, in contrast, the motor 16 is controlled by the controller in such a way that the coil 30 is energized, the rotor 26 is pulled axially to the drive shaft 20 into the position shown in the Fig. 3b The position shown corresponds to the second end position of the fan wheel 14. If both coils 28, 30 are energized, i.e., controlled, the position resulting from the Fig. 3c The position of the rotor 26 is visible and corresponds to the intermediate position of the fan wheel 14. Depending on whether the two coils 28, 30 are connected in series or in parallel, different rotational speeds result for the drive shaft 20 and thus for the fan wheel 14.

[0026] In the Fig. 4 bis 6c A second embodiment of the cooking device according to the invention for carrying out the method according to the invention is shown purely by way of example. The second embodiment is explained below only to the extent of its differences from the first embodiment. Otherwise, reference is made to the above descriptions of the first embodiment. Identical or equivalently functioning components are marked with the same reference numerals.

[0027] In contrast to the first embodiment, the one in the Fig. 4 bis 6c The rotor, which is not explicitly shown, and thus the drive shaft 20, are not axially movable relative to the drive shaft 20 compared to the rest of the motor 16. Instead, in the present second embodiment, the entire motor 16 is moved axially relative to the drive shaft 20, which will be explained in more detail below. For this purpose, the displacement device 24 in the second embodiment has a motor mount 36 for the motor 16, which is movably held on the housing 4, and a motor mount drive 38 connected to the motor mount 36 in a force-transmitting manner. The motor mount 36 is movable axially relative to the drive shaft 20 depending on the control signal of the motor mount drive 38 by means of the control unit. As in the first embodiment, the control unit is also not shown here.

[0028] The motor mount 36 here has a retaining plate 42 which is movably held on the housing 4 by means of a longitudinal guide device 40 of the cooking appliance 2 for the motor mount 36, wherein the longitudinal guide device 40 has four guide pins 44 and corresponding guide openings 46, namely such that the guide pins 44 are arranged on the housing 4 and the guide openings 46 are formed on the retaining plate 42. In the Fig. 5 Only three of the guide pins 44 and three of the guide openings 46 are visible. The motor mounting drive 38, which can be controlled by the control unit, has a spur gear 48, and the mounting plate 42 has a rack 50 that corresponds to and engages with the spur gear 48. See the Fig. 5 .

[0029] Furthermore, the second embodiment is designed such that the supply of fresh air from the free environment can be adjusted essentially independently of the speed of the blower 12.

[0030] For this purpose, a cone 52 is formed on the drive shaft 20 and a cone-shaped boundary surface 54 corresponding to the cone 52 is formed and arranged on the cooking chamber wall 6 that delimits the drive shaft opening 18, such that the cone 52 and the boundary surface 54 form an annular gap 56 for supplying fresh air from a free environment into the cooking chamber 8, wherein a clear cross-section of the annular gap 56 in the Fig. 6a The first end position of the fan wheel 14 shown has a predetermined minimum passage area and in which the Fig. 6c The second end position of the fan wheel 24, as illustrated, has a predetermined maximum through-area. In the present embodiment, it is further provided that the annular gap 56 in the intermediate position of the fan wheel 14 has a clear cross-section with a through-area whose size lies between the minimum and the maximum through-area of ​​the annular gap 56. See the Fig. 6a bis 6c in a summary.

[0031] The following describes the functioning of the second embodiment of the cooking device according to the invention and the method according to the second embodiment with reference to the Fig. 4 bis 6c The extent of the differences compared to the first embodiment is explained in more detail. Otherwise, reference is again made to the first embodiment.

[0032] The food to be cooked (not shown) has been placed in the cooking chamber 8 of the cooking appliance 2, and the cooking chamber door (also not shown) has been closed. The user (not shown) selects a cooking program on the cooking appliance 2 for preparing the food in a manner known to those skilled in the art and starts this cooking program, thus initiating the cooking process. During the cooking process taking place in the cooking chamber 8, the fan wheel 14 is automatically moved axially relative to the drive shaft 20 by means of the sliding device 24 between the first end position, the intermediate position, and the second end position of the fan wheel 14, depending on the cooking program selected on the cooking appliance 2 and the cooking process taking place in the cooking chamber 8, namely depending on at least one cooking parameter determined by means of the at least one sensor (not shown).For this purpose, the motor mounting drive 38 is controlled in the desired manner by means of the control unit, so that the motor mounting drive 38 moves the mounting plate 42 and thus the motor 16 attached to the mounting plate 42 axially to the drive shaft 20 in the respective plane of the image by means of the spur gear 48 and the rack 50. Fig. 4 and 6a bis 6cfrom left to right or from right to left. In this process, analogous to the first embodiment, the fan wheel 14 of the blower 12 is moved and positioned back and forth between the first end position, the intermediate position, and the second end position as desired, for example, depending on the cooking process. In addition, the flow of fresh air from the surrounding environment is adjusted via the annular gap 56. While the clear cross-section of the annular gap 56 has its minimum opening area in the first end position of the fan wheel 14, the clear cross-section of the annular gap 56 increases continuously during the aforementioned movement of the fan wheel 14 from its first end position towards its second end position, until the clear cross-section of the annular gap 56 has its maximum opening area in the second end position of the fan wheel 14.Analogous to the first embodiment, the fan wheel 14 can be positioned in its intermediate position, i.e., between its first and second end positions. In contrast, it would of course also be conceivable that the fan wheel could be positioned in a plurality of intermediate positions. Both a stepwise and a continuous displacement of the fan wheel 14 are possible.

[0033] Due to the inventive design of the cooking appliance and the method according to the present embodiments, namely by the different positioning of the fan wheel 14 of the blower 12 in the cooking chamber 8 axially to the drive shaft 20, the airflow through the cooking chamber 8 can be adjusted, and thus the cooking process taking place in the cooking chamber 8 of the cooking appliance 2 can be influenced as desired. Accordingly, the heat distribution in the cooking chamber 8, and thus the cooking result of a cooking process taking place in the cooking chamber 8 of the cooking appliance 2, can be influenced much more effectively as desired. Thus, the cooking process is not only controllable by means of the speed of the blower 12 for circulating the cooking chamber air, but also by the position of the fan wheel 14 in the cooking chamber 8 axially to the drive shaft 20, for example, behind the rear wall 22 inserted into the cooking chamber 8.In the second embodiment, the amount of supply air, i.e., the amount of fresh air drawn in from the surrounding environment by the fan 12 through the annular gap 56, is also adjustable. This allows the heat distribution in the cooking chamber 8 to be controlled or regulated essentially independently of the fan speed 12, depending on the operating state of the cooking appliance 2 and / or a cooking program selected on the cooking appliance 2 and / or a cooking process in the cooking chamber 8. The positioning of the fan wheel 14 in the aforementioned range between the first and second end positions of the fan wheel 14 axially to the drive shaft 20 can be stepless, i.e., continuous, or in stages. Accordingly, this provides a further possibility of influencing a cooking process and thus the cooking result of a cooking process taking place in the cooking chamber 8 of the cooking appliance 2.In combination with different speeds of the blower 12 for circulating the cooking chamber air and / or with a controlled or regulated steam extraction from the cooking chamber 8, the first and second embodiments offer additional possibilities for varying the rinsing of the cooking chamber 8 of the cooking appliance 2 during an ongoing cooking process.

[0034] The invention is not limited to the present embodiments. For example, the cooking device according to the invention can be freely selected within wide suitable limits, the scope of protection being defined by the claims. See the relevant explanations in the introduction to the description. In particular, the invention is not limited to the design, manufacturing, and circuitry details of the present embodiments. For example, it is conceivable that the two embodiments could be combined within the technical limits.

Claims

1. Cooking appliance (2), comprising a housing (4), a cooking chamber (8) arranged in the housing (4) and delimited by cooking chamber walls (6) of the housing (4), a cooking chamber door for closing a cooking chamber opening (10) of the cooking chamber (8) in a closed position of the cooking chamber door, at least one heater for heating the cooking chamber (8), a fan (12) for circulating cooking chamber air located in the cooking chamber (8), an impeller (14) of the fan (12) being arranged in the cooking chamber (8) and a motor (16) of the fan (12) being arranged outside the cooking chamber (8) on the housing (4), and the impeller (14) being torque-transmittingly connected to the motor (16) by means of a drive shaft (20) which passes through a drive shaft opening (18) in one of the cooking chamber walls (6), and a control means for controlling the heater and the fan (12), it being possible, depending on an operating state of the cooking appliance (2), and / or on a cooking program selected on the cooking appliance (2), and / or on a cooking procedure in the cooking chamber (8), for the impeller (14) to be automatically displaced, axially with respect to the drive shaft (20), between a first end position and a second end position of the impeller (14), and to be positioned in the corresponding end position, by means of a displacement device (24) of the cooking appliance (2), which displacement device is signal-transmittingly connected to the control means, characterised in that, on the drive shaft (20), a cone (52) is formed and arranged and, on the cooking chamber wall (6) that delimits the drive shaft opening (18), a cone-shaped delimiting surface (54) corresponding to the cone (52) of the drive shaft opening (18) is formed and arranged such that the cone (52) and the delimiting surface (54) form an annular gap (56) for supplying fresh air from the open surroundings into the cooking chamber (8), a clear cross section of the annular gap (56) having a predetermined minimum passage area in the first end position of the impeller (14) and having a predetermined maximum passage area in the second end position of the impeller (14).

2. Cooking appliance (2) according to claim 1, characterised in that the displacement device (24) is designed such that, depending on an operating state of the cooking appliance (2), and / or on a cooking program selected on the cooking appliance (2), and / or on a cooking procedure in the cooking chamber (8), the impeller (14) can be automatically positioned, by means of the displacement device (24), at least in one intermediate position of the impeller (14) which is between the first end position and the second end position.

3. Cooking appliance (2) according to claim 1 or claim 2, characterised in that< / b> the cooking appliance (2) comprises at least one sensor, signal-transmittingly connected to the control means, for automatically detecting at least one cooking parameter of the cooking procedure, preferably in that the at least one sensor is in the form of a cooking chamber camera for observing an item to be cooked located in the cooking chamber (8), and / or in the form of a humidity sensor for determining a cooking chamber humidity prevailing in the cooking chamber (8), and / or in the form of a temperature sensor for determining a cooking chamber temperature in the cooking chamber (8) and / or an item temperature of an item to be cooked located in the cooking chamber (8).

4. Cooking appliance (2) according to any of claims 1 to 3, characterised in that the displacement device (24) comprises the motor (16), the motor (16) being designed as a shaded-pole motor such that, depending on the control of a plurality of coils (28, 30) of a stator (32) of the shaded-pole motor (16), the drive shaft (20), which is torque-transmittingly connected to a rotor (26) of the shaded-pole motor (16), automatically moves and positions the impeller (14), by means of the rotor (26) mounted in the stator (32), into its first end position or into its second end position, preferably into its first end position, into its at least one intermediate position or into its second end position.

5. Cooking appliance (2) according to claim 4, characterised in that the plurality of coils (28, 30) is in the form of a first coil (28) and a second coil (30) that is separated from the first coil (28) by means of an electrical insulator (34), the first coil (28) and the second coil (30), as well as the control means, being designed such that the first coil (28) and the second coil (30) can be electrically conductively connected to each other in an electrical series circuit and / or an electrical parallel circuit by means of the control means.

6. Cooking appliance (2) according to the preceding claim, wherein the clear cross section of the annular gap (56) in the at least one intermediate position of the impeller (14) has a passage area, the size of which is between the minimum and the maximum passage area.

7. Cooking appliance (2) according to either of the two preceding claims, wherein the displacement device (24) comprises a motor mount (36) for the motor (16), which motor mount is movably held on the housing (4), and a motor mount drive (38), which is force-transmittingly connected to the motor mount (36), wherein, depending on the control of the motor mount drive (38), the motor mount (36) is movable axially with respect to the drive shaft (20) by means of the control means.

8. Cooking appliance (2) according to the preceding claim, wherein the motor mount (36) comprises, for the motor mount (36), a retaining plate (42), which is movably held on the housing (4) by means of a longitudinal guide device (40) of the cooking appliance (2), preferably in that the longitudinal guide device (40) comprises a plurality of guide pins (44) and corresponding guide openings (46), particularly preferably in that the guide pins (44) are arranged on the housing (4) and the guide openings (46) are arranged or formed in the retaining plate (42).

9. Cooking appliance (2) according to either of the two preceding claims, wherein the motor mount drive (38), which can be controlled by the control means, comprises a spur gear wheel (48), and the retaining plate (42) comprises a gear rack (50) which is designed to correspond to the spur gear wheel (48) and is located so as to engage therewith.

10. Method for operating a cooking appliance (2) according to any of the preceding claims, wherein, depending on an operating state of the cooking appliance (2), and / or on a cooking program selected on the cooking appliance (2), and / or on a cooking procedure in the cooking chamber (8), the impeller (14) is automatically displaced, axially with respect to the drive shaft (20), between a first end position and a second end position of the impeller (14), and is positioned in the corresponding end position, by means of a displacement device (24).

11. Method according to the preceding claim, wherein, depending on an operating state of the cooking appliance (2), and / or on a cooking program selected on the cooking appliance (2), and / or on a cooking procedure in the cooking chamber (8), the displacement device (24) automatically positions the impeller (14) at least in one intermediate position of the impeller (14) which is between the first end position and the second end position.

12. Method according to either of the two preceding claims, wherein the cooking appliance (2) comprises at least one sensor signal-transmittingly connected to the control means, by means of which sensor at least one cooking parameter of the cooking procedure is automatically detected, preferably in that an item to be cooked located in the cooking chamber (8) is observed by means of the at least one sensor in a camera-based manner, and / or a cooking chamber humidity prevailing in the cooking chamber (8) is determined, and / or a cooking chamber temperature in the cooking chamber (8) and / or an item temperature of an item to be cooked located in the cooking chamber (8) is determined.