HOUSEHOLD APPLIANCE DEVICE

Description

[0001] The invention relates to a household appliance according to the preamble of claim 1 and to a method for producing a ferrite element for a household appliance according to claim 8.

[0002] A household appliance with at least one ferrite element is already known from the prior art. This element is designed to concentrate a magnetic flux provided by a coil. The ferrite element consists of a portion of MnO, a portion of ZnO, and a portion of Fe2O3 and is referred to as an MnZn ferrite element. The ferrite element does not contain any other materials.

[0003] Furthermore, EP 0 158 353 A2 and JP S60 230394 A each disclose a ferrite element whose material composition consists of a mixture of various ferrites. The two aforementioned publications provide the molar fractions of the different materials in the ferrite element.

[0004] The object of the invention is, in particular, to provide a generic device with improved properties in terms of efficiency. This object is achieved according to the invention by the features of claims 1 and 8, while advantageous embodiments and further developments of the invention can be found in the subclaims.

[0005] The invention is based on a household appliance, in particular a cooking appliance and advantageously a hob appliance, comprising at least one ferrite element, which is provided for concentrating a magnetic flux provided by a coil and which comprises at least a proportion of MnO, wherein the ferrite element comprises at least a proportion of NiO, whereby efficiency, in particular heating efficiency, can be improved. In particular, high performance, in particular of the ferrite element and advantageously additionally of a household appliance comprising the household appliance, can be achieved, advantageously during a cooking process.In particular, a cooking process can be maintained for a long time without any adjustments that might be necessary, in particular to protect cooking appliance components and / or to ensure a safe working area for cooking appliance components. At high temperatures, in particular, low power losses can be achieved, and in particular lower power losses than with an MnZn ferrite element, which consists in particular of a proportion of MnO, a proportion of ZnO and a proportion of Fe 2 O 3. In particular, the proportion of NiO can enable an advantageously high Curie temperature of the ferrite element, which is in particular higher than a known Curie temperature of an MnZn ferrite element, which consists in particular of a proportion of MnO, a proportion of ZnO and a proportion of Fe 2 O 3.

[0006] A "household appliance device," in particular a "cooking appliance device," advantageously a "hob device," and particularly advantageously an "induction hob device" is to be understood as at least one part, in particular a subassembly, of a household appliance, in particular a cooking appliance, advantageously a hob, and particularly advantageously an induction hob. For example, a household appliance comprising the household appliance device could be a freezer, advantageously a refrigerator and / or a freezer. Alternatively or additionally, a household appliance comprising the household appliance device could be, for example, a dishwasher and / or a washing machine and / or a dryer. Advantageously, a household appliance comprising the household appliance device is a cooking appliance.A household appliance designed as a cooking appliance could, for example, be an oven and / or a microwave and / or a grill and / or a steamer. A household appliance designed as a cooking appliance is advantageously a hob, preferably an induction hob.

[0007] A "ferrite element" is understood in particular to mean an element that consists at least largely of ferrites. "Ferrites" are understood in particular to mean ferromagnetic and / or ferrimagnetic ceramic materials. "At least largely" is understood in particular to mean a proportion of at least 70%, in particular at least 80%, advantageously at least 90%, and preferably at least 95%. In particular, the ferrite element is intended to improve the coupling between the coil and at least one cooking utensil that is positioned in an installed position, in particular at least partially above the coil.The ferrite element is provided, in particular, to significantly amplify a magnetic flux provided by the coil and thus to amplify and / or increase heat losses induced in the cooking utensil, in particular in a cooking utensil base, particularly in comparison to a design that avoids a ferrite element. In particular, the ferrite element is provided to at least partially shield at least one location from a magnetic flux provided by the coil. The ferrite element is provided, in particular, to minimize stray fields provided by the coil.

[0008] The household appliance device, in particular, comprises the coil. In particular, the coil comprises at least one induction heating cable. A "coil" is understood, in particular, to be an inductive component with at least one particularly specific inductance. In particular, the coil is designed at least substantially in the shape of a disk, in particular in the shape of a circular disk, alternatively in the shape of an oval or a rectangle. In particular, the coil comprises at least five, in particular at least ten, advantageously at least fifteen, and preferably at least twenty windings of the induction heating cable. For example, windings of at least one coil section could be arranged in several planes. Preferably, windings of at least one coil section are arranged in one plane.

[0009] The phrase that an object has at least a "proportion of" another object should be understood in particular to mean that the object consists of the other object to a mass fraction and / or volume fraction of more than 0%. MnO is in particular manganese(II) oxide. The ferrite element in particular has a mass fraction and / or volume fraction of at least 5%, in particular of at least 10%, advantageously of at least 15% and preferably of at least 20% of MnO. In particular, the ferrite element has a mass fraction and / or volume fraction of at most 40%, in particular of at most 35%, advantageously of at most 30% and preferably of at most 25% of MnO. NiO is in particular nickel(II) oxide.

[0010] "Intended" should be understood in particular as specifically designed and / or equipped. The fact that an object is intended for a specific function should be understood in particular as meaning that the object fulfills and / or performs this specific function in at least one application and / or operating state.

[0011] For example, the coil could be designed as a choke. Preferably, the household appliance device has the coil designed as an induction heating element. The coil designed as an induction heating element is particularly intended to generate an alternating electromagnetic field, in particular with a frequency of 20 kHz to 100 kHz, which is particularly intended to be converted into heat in a set-up, in particular metallic, preferably ferromagnetic, cooking utensil base through eddy current induction and / or remagnetization effects. This enables, in particular, optimized heating of set-up cooking utensils.

[0012] The ferrite element has a mass fraction and in particular a volume fraction of at least 0.5%, in particular of at least 1%, advantageously of at least 1.5%, particularly advantageously of at least 2% and preferably of at least 2.5% of NiO, whereby in particular improved performance can be achieved.

[0013] The ferrite element has a mass fraction and in particular a volume fraction of maximum 10%, in particular of maximum 8%, advantageously of maximum 7%, particularly advantageously of maximum 6% and preferably of maximum 5% of NiO, whereby in particular an excessively high proportion of NiO and / or a reversal of a positive effect on the performance caused by the proportion of NiO can be avoided.

[0014] It is further proposed that the ferrite element contain at least a portion of ZnO. The ferrite element has, in particular, a mass fraction and / or volume fraction of at least 2%, in particular of at least 3%, advantageously of at least 4%, and preferably of at least 5% of ZnO. In particular, the ferrite element has a mass fraction and / or volume fraction of at most 20%, in particular of at most 15%, advantageously of at most 10%, and preferably of at most 8% of ZnO. ZnO is, in particular, zinc oxide. This makes it possible to achieve a cost-effective design.

[0015] It is also proposed that the ferrite element contain at least a proportion of Fe 2 O 3 . The ferrite element has, in particular, a mass fraction and / or volume fraction of at least 50%, in particular of at least 55%, advantageously of at least 60% and preferably of at least 65% of Fe 2 O 3 . In particular, the ferrite element has a mass fraction and / or volume fraction of at most 90%, in particular of at most 85%, advantageously of at most 80% and preferably of at most 75% of Fe 2 O 3 . Fe 2 O 3 is, in particular, iron(III) oxide. This makes it possible, in particular, to achieve a cost-effective design.

[0016] Furthermore, it is proposed that the ferrite element have a Curie temperature of at least 250°C, in particular of at least 260°C, advantageously of at least 270°C, particularly advantageously of at least 280°C, and preferably of at least 290°C, which allows for and / or enables a cooking process at particularly high temperatures. In particular, high functional capability can be ensured even at high temperatures.

[0017] It is further proposed that the ferrite element have an initial permeability of at least 3000, in particular of at least 3200, advantageously of at least 3400, particularly advantageously of at least 3600, and preferably of at least 3800, in particular at a frequency of at least substantially 10 kHz and in particular at a magnetic flux of at least substantially 0.1 mT and in particular at a temperature in a range from 180°C to 200°C. The initial permeability of the ferrite element is in particular a permeability before the ferrite element is magnetized, in particular for the first time. In this context, "at least substantially" is to be understood in particular as meaning that a deviation from a predetermined value deviates in particular by less than 25%, preferably less than 10%, and particularly preferably less than 5% of the predetermined value.As a result, a magnetic flux provided by the coil can be amplified particularly strongly, whereby in order to generate the same heat in a cooking utensil base of an installed cooking utensil, in particular a lower magnetic flux has to be generated than in a design with a ferrite element with a lower initial permeability.

[0018] In particular, the ferrite element has a saturation flux density of at least 150 mT, in particular of at least 200 mT, advantageously of at least 250 mT and preferably of at least 300 mT, in particular at a frequency of at least substantially 10 kHz and in particular at a magnetic field strength of at least substantially 1200 A / m and in particular at a temperature of at least substantially 200°C.

[0019] The ferrite element is in particular intended to cause power losses of a maximum of 150 mW / cm 3 , in particular of a maximum of 120 mW / cm 3 , advantageously of a maximum of 100 mW / cm 3 , particularly advantageously of a maximum of 80 mW / cm 3 and preferably of a maximum of 65 mW / cm 3 , in particular at a frequency of at least substantially 20 kHz and in particular at a magnetic flux of at least substantially 200 mT and in particular at a temperature of at least substantially 200°C. In particular, the ferrite element is intended to cause maximum power losses at a temperature of at least substantially 190°C.

[0020] Particularly high performance can be achieved in particular by a method for producing a household appliance with at least one ferrite element which is provided for bundling a magnetic flux provided by a coil and which has at least a proportion of MnO, at least a proportion of ZnO and at least a proportion of NiO, wherein a ratio of Mn to Zn with a varying proportion of NiO is kept at least substantially and in particular completely constant. As the proportion of NiO increases, the proportions of MnO and ZnO are reduced to the same extent. In particular, when a proportion of NiO changes, a quotient of the proportion of MnO and the proportion of ZnO is kept at least substantially and in particular completely constant.

[0021] The household appliance device is not intended to be limited to the application and embodiment described above. In particular, the household appliance device may have a number of individual elements, components, and units that differs from the number stated herein to fulfill a functionality described herein.

[0022] Further advantages will become apparent from the following description of the drawings. The drawings illustrate exemplary embodiments of the invention. The drawings, the description, and the claims contain numerous features in combination.

[0023] They show: Fig. 1 shows a household appliance with a household appliance device in a schematic plan view and Fig. 2 shows a coil designed as an induction heating element and five ferrite elements of the household appliance device in a schematic view from below onto the coil.

[0024] Fig. 1shows a household appliance 16 with a household appliance device 10. The household appliance 16 could, for example, be designed as a refrigerator and / or as a washing machine. In the present exemplary embodiment, the household appliance 16 is designed as a cooking appliance, in particular as an induction cooking appliance. For example, the household appliance 16 could be designed as an oven, in particular as an induction oven, and / or as a stove, in particular as an induction stove, and / or as a cooking oven, in particular as an induction cooking oven. The household appliance 16 is designed as a hob, in particular as an induction hob. The household appliance device 10 in the present exemplary embodiment is designed as a cooking appliance device, in particular as an induction cooking appliance device. The household appliance device 10 is designed as a hob device, in particular as an induction hob device.

[0025] The household appliance device 10 has a household appliance plate 18. In an assembled state, the household appliance plate 18 forms part of an outer housing of the appliance, in particular of the household appliance 16. In an installed position, the household appliance plate 18 forms a part of the outer housing of the appliance facing an operator. The household appliance plate 18 could, for example, be designed as a front panel and / or cover panel of the outer housing of the appliance, in particular of a household appliance 16 designed as an oven and / or a stove and / or a cooking oven and / or a refrigerator and / or a washing machine. In the present exemplary embodiment, the household appliance plate 18 is designed as a hob plate. In an assembled state, the household appliance plate 18 is intended for placing cooking utensils thereon.

[0026] The household appliance device 10 has a user interface 20 for input and / or selection of operating parameters (cf. Fig. 1 ), for example, a heating power and / or a heating power density and / or a heating zone. The operator interface 20 is provided to output a value of an operating parameter to an operator. For example, the operator interface 20 could output the value of the operating parameter to an operator visually and / or acoustically.

[0027] The household appliance 10 has a control unit 22. The control unit 22 is designed to execute actions and / or change settings depending on operating parameters entered via the user interface 20.

[0028] In the present embodiment, the household appliance device 10 has a plurality of coils 14 (cf. Fig. 2). Only one of the coils 14 is shown. For example, at least some of the coils 14 could be arranged in the form of a matrix. Alternatively or additionally, at least some of the coils 14 could each form an independent heating zone. The coils 14 are essentially identical, which is why only one of the coils 14 is described below.

[0029] Coil 14 is designed as an induction heating element. Coil 14 is intended to heat cooking utensils placed above coil 14 in an installed position on appliance plate 18. In an operating state, coil 14 supplies energy to the placed cooking utensils. Control unit 22 regulates the energy supply to coil 14 in an operating state. In an installed position, coil 14 is arranged below appliance plate 18.

[0030] The household appliance device 10 has at least one coil carrier 24 (cf. Fig. 2 ). The household appliance device 10 has exactly one coil carrier 24 per coil 14. The coil 14 is arranged in an installed position on the coil carrier 24.

[0031] In the present embodiment, the household appliance 10 has five ferrite elements 12, in particular for each coil 14 (cf. Fig. 2). Of objects present in multiple quantities, only one is provided with a reference symbol in the figures. Alternatively, the household appliance device 10 could have a smaller number of ferrite elements 12, such as two, in particular three or advantageously four ferrite elements 12, in particular for each coil 14. The household appliance device 10 could alternatively have a larger number of ferrite elements 12, such as at least six, in particular at least eight and advantageously at least ten ferrite elements 12, in particular for each coil 14. The ferrite elements 12 are essentially identical, which is why only one ferrite element 12 of the ferrite elements 12 is described below.

[0032] In an assembled state, the ferrite element 12 is arranged, in particular fastened, to the coil carrier 24. The ferrite element 12 is intended to concentrate a magnetic flux provided by a coil 14. In an installed position, the ferrite element 12 is arranged below the coil 14.

[0033] The ferrite element 12 contains a proportion of MnO. In the present exemplary embodiment, the ferrite element 12 contains a proportion of essentially 19.93% MnO. In addition to the proportion of MnO, the ferrite element 12 also contains a proportion of NiO.

[0034] Ferrite elements 12 with different NiO contents are conceivable. The following table summarizes some examples of ferrite elements 12 with different NiO contents. A ferrite element 12 designated "F01" is prior art and not according to the invention. F01 F01Ni08 F01Ni16 F01Ni24 F01Ni32 F01Ni40 F01Ni48 Fe 2 O 3 [%] 71,50 71,50 71,50 71,50 71,50 71,50 71,50 MnO [%] 22,45 21,82 21,19 20,56 19,93 19,30 18,67 ZnO [%] 6,05 5,88 5,71 5,54 5,37 5,20 5,03 NiO [%] 0,00 0,80 1,60 2,40 3,20 4,00 4,80 Total [%] 100,00 100,00 100,00 100,00 100,00 100,00 100,00 Mn / Zn 3,71 3,71 3,71 3,71 3,71 3,71 3,71 Fe / Mn 3,18 3,28 3,37 3,48 3,59 3,71 3,83 Curie temperature [°C] 250 260 270 280 290 300 310 Saturation flux density [mT] 242 256 279 292 306 318 329 Power losses [mW / cm 3< ] 87 74 64 61 65 76 91 Position of power losses [°C] 80 100 140 160 180 190 210 Initial permeability 3919 4090 3904 3968 3834 3512 3234

[0035] In series of tests conducted with the various ferrite elements 12 listed in the table, a ferrite element 12 designated "F01Ni32" proved to be particularly preferred. This ferrite element 12, designated "F01Ni32," is described below.

[0036] In the present exemplary embodiment, the ferrite element 12 has a proportion, in particular a mass fraction and / or volume fraction, of essentially 3.2% NiO. In addition to the MnO and NiO fractions, the ferrite element 12 also has a ZnO fraction. In the present exemplary embodiment, the ferrite element 12 has a ZnO fraction of essentially 5.37%.

[0037] The ferrite element 12 has, in particular, in addition to the proportion of MnO, the proportion of ZnO, and the proportion of NiO, a proportion of Fe 2 O 3. In the present exemplary embodiment, the ferrite element 12 has a proportion of essentially 71.50% Fe 2 O 3.

[0038] The ferrite element 12 has a Curie temperature of substantially 290°C. In the present embodiment, the ferrite element 12 has a saturation flux density of substantially 306 mT, particularly at a frequency of substantially 10 kHz and at a magnetic field strength of substantially 1200 A / m and at a temperature of substantially 200°C.

[0039] The ferrite element 12 is designed to cause power losses of substantially 65 mW / cm 3 , particularly at a frequency of substantially 20 kHz and at a magnetic flux of substantially 200 mT and at a temperature of substantially 200°C. The ferrite element 12 is designed to cause maximum power losses at a temperature of substantially 180°C.

[0040] In the present embodiment, the ferrite element 12 has an initial permeability of substantially 3834. In a method for manufacturing the ferrite element 12 for the household appliance 10, a ratio of Mn to Zn is kept substantially constant with varying proportion of NiO. Reference symbol

[0041] 10Household appliance device 12Ferrite element 14Coil 16Household appliance 18Household appliance plate 20Operator interface 22Control unit 24Coil carrier

Claims

1. Household appliance device, in particular hob device, having at least one ferrite element (12), which is provided for concentrating a magnetic flux supplied by a coil (14), and which has at least one proportion of MnO, wherein the ferrite element (12) has at least one proportion of NiO, characterised in that the ferrite element (12) has a mass proportion of at least 0.5% of NiO, wherein the ferrite element (12) has a mass proportion of at most 10% of NiO.

2. Household appliance device according to claim 1, characterised by the coil (14), which is embodied as an induction heating element.

3. Household appliance device according to one of the preceding claims, characterised in that the ferrite element (12) has at least one proportion of ZnO.

4. Household appliance device according to one of the preceding claims, characterised in that the ferrite element (12) has at least one proportion of Fe2O3.

5. Household appliance device according to one of the preceding claims, characterised in that the ferrite element (12) has a Curie temperature of at least 250°C.

6. Household appliance device according to one of the preceding claims, characterised in that the ferrite element (12) has an initial permeability of at least 3000.

7. Household appliance, in particular hob, having at least one household appliance device (10) according to one of the preceding claims.

8. Method for producing a household appliance device (10), according to one of claims 1 to 6, having at least one ferrite element (12), which is provided for concentrating a magnetic flux supplied by a coil (14), and which has at least one proportion of MnO, at least one proportion of ZnO and at least one proportion of NiO, characterised in that a ratio of Mn to Zn with a varying proportion of NiO is kept at least essentially constant, wherein with an increasing proportion of NiO, the proportions of MnO and ZnO are reduced to the same degree, wherein the ferrite element (12) has a mass proportion of at most 10% of NiO.