An induction HOB with a heat sink

Abstract

The invention relates to an induction hob comprising a housing (10) with a ventilation opening (14); an induction first heating element (20) and a second heating element (40) mounted spaced apart within the housing (10); a fan (50) that cools the first heating element (20) via a first air flow path (f1 ) progressing towards the first heating element (20) from the air outlet by accelerating the ambient air supplied from the ventilation opening (14), and cools via a second air flow path (f2) progressing from the first heating element (20) to the second heating element (40). The induction hob includes a monoblock metal heat sink (30) extending between the first and second heating elements (20, 40), over which the second air flow path (f2) passes entirely without deviating from its direction, comprising a linear first tunnel (T1) and a parallel and spaced linear second tunnel (T2); and a linear upper channel (32) extending between the tunnels (T1, T2) and through which the second air flow path (f2) passes without deviating from its direction.

Description

[0001] AN INDUCTION HOB WITH A HEAT SINK

[0002] TECHNICAL FIELD

[0003] The present invention relates to an induction hob wherein the cooling system having a fan, particularly to an induction hob in which the air conveyed by the fan passes through a heat sink.

[0004] STATE OF THE ART

[0005] Providing effective cooling performance in induction hobs is of great importance to enhance the performance, durability, and safety of the hobs. Induction hobs, which use high-power and high-frequency electrical energy, cause heating of the coils and other components. This heating can adversely affect the performance of the hobs and shorten the lifespan of the components. However, these problems can be prevented with an effective cooling system.

[0006] In induction hobs, the cooling process is carried out with fans and heat sinks. While fans cool the coils, heat sinks cool the power electronics elements on them. Designing heat sinks according to specifications is important in terms of directing the air received from the fan to the desired region. Additionally, well-designed heat sinks increase heat transfer in high- temperature regions. Cooling fans are used in induction hobs to provide direct air flow to the coils and IGBT elements. Axial fans are generally preferred. Axial fans provide parallel air flow, creating air movement in a large volume, and they generally move air by pushing it in a single direction.

[0007] EP4096362 describes an electric range comprising a case, a cover plate being coupled to an upper end of the case to allow an object to be heated to be placed on an upper surface thereof, a heat sink, an air blowing fan, wherein the air blowing fan is configured to discharge air toward the heat sink, and an air guide formed to be in communication with the air blowing fan, and arranged to surround the heat sink to form a flow path of air that cools the heat sink, wherein the air guide is provided with an side outlet being formed in a portion in which the air guide communicates with the air blowing fan, and wherein the air guide is configured to discharge a portion of air flowing from the air blowing fan outward. BRIEF DESCRIPTION OF THE INVENTION

[0008] The object of the invention is to increase the cooling efficiency of the heat sink found in induction hobs.

[0009] In order to achieve the aforementioned objective, the invention relates to an induction hob comprising a housing with a ventilation opening; an induction first heating element and a second heating element mounted spaced apart within the housing; a fan that cools the first heating element via a first air flow path progressing towards the first heating element from the air outlet by accelerating the ambient air supplied from the ventilation opening, and cools via a second air flow path progressing from the first heating element to the second heating element. The induction hob includes a monoblock metal heat sink extending between the first and second heating elements, over which the second air flow path passes entirely without deviating from its direction, comprising a linear first tunnel and a parallel and spaced linear second tunnel; and a linear upper channel extending between the tunnels and through which the second air flow path passes without deviating from its direction. The tunnel allows the cooling air in the second air flow path to be directed together from both the top and bottom of the heat sink without encountering obstacles, ensuring both the cooling of the second heating element and the cooling of the heat sink itself. When the heat sink is attached directly to the power electronics components on the housing to provide conduction, cooling these components with cooling air becomes possible. Furthermore, when cooling air is conveyed over the heat sink, for example, to create laminar flow, it has been surprisingly found that it does not disrupt this flow. In this way, cooling air flow noise is eliminated.

[0010] Preferably, the upper channel is divided in the direction of the second air flow path by a partition wall. The partition wall increases the heat convection efficiency by increasing the air flow area.

[0011] Preferably, the partition wall is singular in the upper channel and divides the upper channel equally along its length into a first channel and a second channel. By adjusting the air flow cross-sectional areas of the equally divided channels to be equal to that of the tunnels, changes in the air flow profile during passage over the heat sink, such as turbulence formation, are prevented.

[0012] Preferably, the widths of the first channel and the second channel are adjusted to direct the hot air flow caused by the heat generated on the heat sink upward. In this way, the heat generated when the heat sink heats up due to the circuit underneath is dissipated from the heat sink through convection as the heated air progresses upward between the first and second channels.

[0013] Preferably, the heat sink is a monolithic structure made of aluminum extrusion. With aluminum extrusion, both the channels and tunnels are obtained in a single process, and high heat transfer efficiency is achieved.

[0014] Preferably, the first tunnel and the second tunnel are arranged adjacent and parallel to the opposite edges of the upper channel, respectively. In this way, the regional velocity loss profile of the cooling air becomes similar, and it has been found that the air progresses more quietly compared to different profiles.

[0015] Preferably, an outwardly adjacent third tunnel is provided to the second tunnel in the heat sink. The third tunnel allows the heat sink to be extended in the transverse direction. This increases efficiency. Additionally, in configurations where multiple pairs of heating elements are present on the hob housing, it allows the use of the same type of heat sink in similar fan structures in left-right applications.

[0016] Preferably, the heat sink includes a third channel provided in the form of an inward recess on an inner edge close to the second tunnel. The third channel eliminates thermal accumulations caused by the extension of the inner edge by increasing the air passage area.

[0017] Preferably, the aforementioned third channel is arranged perpendicular to the third tunnel. In this way, an equal cooling profile of the cooling air on the base of the heat sink is ensured.

[0018] Preferably, the heat sink includes an inclined extension extending toward its inner wall. The inclined extension allows the wall thickness of the portion of the heat sink extending toward the inner wall to be reduced. In this way, cooling efficiency increases.

[0019] Preferably, the ventilation opening is provided on the base plate of the housing so that it remains under the fan air inlet, and includes a deflector plate that pressurizes the air flow by forming a second air flow path at an angle with the first air flow at the fan’s air outlet, directing the air flow rate radially towards the second heating element. Additionally, the axial fan power is adjusted to cool the second heating element alone via the second air flow rate. This structure provides both the cooling of the heat sink and the cooling of the second heating element with a single axial fan. A quiet cooling system is obtained compared to conventional multi-fan cooling systems. In this way, the operating noise of the hob during cooking is reduced.

[0020] Preferably, the fan is an axial fan, and the ventilation opening is aligned coaxially with a first coil of the first heating element and the fan. In this case, the energy expended for the fan to cool the first heating element alone decreases, and effective cooling is achieved both in the heat sink and the second heating element with the pressurized air obtained with the fan power progressing in the second air flow path.

[0021] Preferably, a deflector plate is arranged to partially shield the fan outlet from above. The deflector plate imparts both axial and radial fan characteristics to the axial fan with a very simple construction change. In this way, the need for an expensive radial fan is eliminated.

[0022] Preferably, from the front edge of the deflector plate, a side wall that circumferentially surrounds the impeller of the axial fan and a nozzle-shaped fan outlet arranged to face the second heating element on the side wall, covered from above by the deflector plate, are included. The nozzle structure allows the air to be accelerated in the radial direction by reducing the cross-section. In this way, it becomes possible for a single axial fan to cool the coils of both the first and second heating elements.

[0023] Preferably, a diffuser element is positioned in the second air flow path to distribute the second air flow under the second heating element and is adjacent from one end to a front wall of the heat sink. In this way, the cooling air, which first passes through the heat sink by progressing in a narrow cross-sectional area along the second air flow path, is then taken into a large cross-sectional area towards the underside of the second heating element, ensuring homogeneous cooling of the second heating element.

[0024] Preferably, the diffuser element includes angled fins arranged to expand from an inlet portion towards the center of the second heating element and placed at one end on the corresponding upper channel and lower tunnel walls. The fins ensure that the corridor formed with the walls of the upper channel and lower tunnel continues towards under the second heating element and direct the air flow to cool the heating element entirely from below as desired. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a perspective assembly view of the representative construction of the induction hob with an axial fan according to the invention.

[0026] Figure 2 is an exploded view of the induction hob shown in Figure 1 with the axial fan disassembled.

[0027] Figure 3 is a cross-sectional view of a representative construction of the monolithic heat sink of the induction hob.

[0028] Figure 4 is a perspective view of the representative construction of the heat sink given in Figure 3.

[0029] Figure 5 is a top view showing the diffuser under the second heating element of a cooling system used in the induction hob according to the invention.

[0030] DETAILED DESCRIPTION OF THE INVENTION

[0031] In this detailed description, the development subject to the invention is described with references to examples, solely to better explain the subject without any limitation.

[0032] In Figure 1 , a representative construction of the induction hob according to the invention is shown in perspective with an open-top metal tray-shaped housing (10) with its ceramic glass top plate removed. In the housing (10) of the induction hob, there is a first heating element (20) and a second heating element (40) controlled by a single circuit board (80). The housing (10) has a flat and planar base plate (12) and flat strip-shaped side edges (11 ) surrounding the perimeter of the base plate (12) perpendicularly. The top plate (not shown) is placed flatly on top of the side edges (11 ). The first and second heating elements (20, 40) have the same structure and provide heating by induction. For this purpose, the first heating element and the second heating element (20, 40) include respective flat first coil (24) and second coil (44), which are wound in interleaved hexagonal rings. The first and second coils (24, 44) are fixed at a distance from each other to the base plate (12) with circular frames (22, 42) on which they are mounted. The electronic circuit board (80) extends under the frames (22, 42). An IGBT circuit that generates high heat is located on the upper wall of the circuit board (80). A prismatic heat sink (30) made of aluminum is placed in a way that it provides heat conduction, extending between the frames (22, 42) on the upper wall (82) of the circuit board (80), close to the side edge (11 ) of the base plate (12).

[0033] In Figure 2, the components on the induction hob are shown exploded. A ventilation opening (14) is provided on the base plate (12) of the housing (10) concentric with the center of the first coil (24) adjacent to the corner. The ventilation opening (14) is in the form of a circular grille and allows the external ambient air to pass into the housing (10). A fan housing (60) sits on the base plate (12) concentrically with the ventilation opening (14) via a circular side wall (62). The fan housing (60) has a deflector plate (64) on the side wall (62) that covers half of the fan outlet surrounded by the upper edge of the side wall (62). The deflector plate (64), together with the side wall (62) in the form of a circular strip, forms a structure similar to a radial fan casing with a partially open top surface. On the side of the side wall (62) facing the second heating element (40), an extension with a partially rectangular cross-section is made to form a nozzle-shaped fan outlet (66). The fan outlet (66) is connected via a flat bridge element (68) facing the inlet (72) of an opposing diffuser element (70). The diffuser element (70) and the fan housing (60) are produced as a monoblock by plastic injection molding. An aluminum monoblock heat sink (30) extending along its length is mounted on the bridge element (68) and has a rectangular prismatic structure. The heat sink (30) is adjacent to the fan outlet (66) at one end and to the inlet (72) of the diffuser element (70) at the other end.

[0034] An impeller (56) mounted on its rotation axis is placed together with a motor (54) to the side wall (62) of the fan housing (60). The motor (54) and the impeller (56) rotatably connected to it are fixed at their center to a mounting bracket (52) in the form of a plastic bridge. The mounting bracket (52) is locked onto the upper edge of the side wall (62) from its opposite ends. When the axial fan (50) is mounted on the fan housing (60), its impeller (56) rotates and creates low pressure at the ventilation opening (14), drawing external ambient air into the housing (10). Since the rotation axis of the axial fan (50) is perpendicular to the base plate (12), the ambient air passes through the axial fan (50) and reaches the first heating element (20) directly from the open part of the side wall (62).

[0035] The diffuser element (70) has a base plate (74) similar to a truncated circle with raised peripheral edges (75). The base plate (74) extends at a distance under the coil (44) of the second heating element (40), forming an air passage corridor.

[0036] In Figures 3 and 4, the heat sink (30) is shown in perspective representation. The heat sink (30) is a monoblock aluminum extrusion profile similar to a rectangle and extends along its length with a lower tunnel (34) having first, second, and third tunnels (T1 , T2, T3), and an upper channel (32) parallel to each other. The upper channel (32) is obtained by bending an upper flat outer edge (37) adjacent and parallel to the side edge (11) of the housing (10) to form a W-like cross-sectional shape. In this way, the upper channel (32) is equally divided into two parts by a vertical partition wall (322) with its free end facing upwards. Thus, a first channel (K1) and a second channel (K2) that are parallel and adjacent to each other are obtained. The widths of the first channel (K1) and the second channel (K2) obtained by dividing the upper channel (32) are adjusted to be at least 0.5 mm. This distance is sufficient for the heat generated on the heat sink (30) to be dissipated through convection.

[0037] Continuing from this, a lower tunnel (34) with an inverted W-shaped cross-sectional form includes the second and third tunnels (T2, T3). The second and third tunnels (T2, T3) are separated by a vertical intermediate wall (343) with its free end facing downwards. An inner edge (36) opposite to the outer edge (37) has an inward-facing third channel (K3) along its length. Additionally, the upward-facing surface of the lower tunnel (34) is given an inclined extension (35) downward, forming an inward wedge shape. It has been determined that the described profile of the heat sink (30) effectively cools the heat sink (30) with the cooling air progressing in the second air flow direction, and does not disturb the flow profile during this time. The rear wall (31) of the heat sink (30) abuts the inlet (72) of the diffuser element (70). Indeed, each vertical edge of the profile of the first and second tunnels (T1 , T2) abuts a corresponding fin (b-e) placed at the inlet (72). Here, the adjacent wall of the first tunnel (T1) where the outer edge (37) is located abuts the peripheral edge (75). Thus, respectively, the first tunnel (T1 ), first channel (K1 ), second channel (K2), second tunnel (T2), third tunnel (T3), and third channel (K3) extend along from the rear wall (33) to the front wall (31), forming the heat sink (30). The vertical walls of the heat sink (30) have an undulated form on the parts facing the corridors they delimit. The undulated form increases heat transfer performance by increasing the contact area. As shown in Figure 5, the gaps in the expanding parts of the fins (a-e) distribute the third air flow path (f3) along the inlet of the base plate (74) by widening it.

[0038] In Figure 5, the fan housing (60) and the associated diffuser element (70), which form the air guide channel inside the housing (10), are shown in perspective. The fan housing (60) is in the form of a radial fan casing with a half-circle cut from the top, providing the axial fan (50) outlet. Next to the axial air flow path (f 1 ) perpendicular to the base plate (12) above the axial fan (50), the pressurized air is radially discharged in the part covered by the deflector plate (64) through the nozzle-shaped fan outlet (66), providing an air flow in the direction of the second air flow path (f2). The second air flow path (f2) is adjacent and parallel to the side edge (11 ) of the housing (10). When the pressurized air is discharged from the fan outlet (66), it passes over the bridge element (68) and is taken into the diffuser element (70) having an inlet (72) of equal width to the fan outlet (66), passing through a protrusion (73) and gaining an upward velocity vector. As shown in Figure 4, the air passing through the protrusion (73) is passed between angled fins (a-e) that are adjacent and expanding, and distributed over the flat and planar base plate (74) to form a largely homogeneous and laminar third air flow path (f3). When the axial fan (50) is operated, the motor (54) attached to the mounting bracket (52) rotates the impeller (56) in the direction perpendicular to the base plate (12), and the air drawn from the ventilation opening (14) passes through the open part of the side wall (62) of the fan housing (60) directly towards the first heating element (20), cooling the first coil (24) on the frame (22). In the part covered by the deflector plate (64) on the side wall (62), the air pressure increases in the enclosed volume formed with the adjacent side wall (62) portion, and is radially discharged from the fan outlet (66). The air flow in the blowing direction of the axial fan (50) forms the first air flow path (f1), and the radial air flow forms the second air flow path (f2) perpendicular to the first air flow path (f1 ). The air discharged from the fan outlet (66) follows the second air flow path (f2) and passes over the heat sink (30) from a front wall (31 ) adjacent to the fan outlet (66) to a rear wall (33) at the opposite end.

[0039] REFERENCE NUMERALS

[0040] 10 Housing 56 Impeller

[0041] 11 Side edge 60 Fan housing

[0042] 12 Base plate 62 Side wall

[0043] 14 Ventilation opening 64 Deflector plate

[0044] 16 Outlet hole 66 Fan outlet

[0045] 20 First heating element 68 Bridge element

[0046] 22 Frame 70 Diffuser element

[0047] 24 First coil 72 Inlet

[0048] 30 Heat sink 73 Protrusion

[0049] 31 Front wall 74 Base plate 2 Upper channel 75 Peripheral edge 22 Partition wall 80 Circuit board

[0050] 33 Rear wall 82 Upper wall

[0051] 34 Lower tunnel T1 First tunnel

[0052] 343 Intermediate wall T2 Second tunnel

[0053] 35 Inclined extension T3 Third tunnel

[0054] 36 Inner edge K1 First channel

[0055] 37 Outer edge K2 Second channel

[0056] 40 Second heating element K3 Third channel

[0057] 42 Frame f1 First air flow path

[0058] 44 Second coil f2 Second air flow path

[0059] 50 Fan f3 Third air flow path

[0060] 52 Mounting bracket a-e Fins

[0061] 54 Motor

Claims

CLAIMS1. An induction hob comprising a housing (10) with a ventilation opening (14); an induction first heating element (20) and a second heating element (40) mounted spaced apart within the housing (10); a fan (50) that cools the first heating element (20) via a first air flow path (f1) progressing towards the first heating element (20) from the air outlet by accelerating the ambient air supplied from the ventilation opening (14), and cools via a second air flow path (f2) progressing from the first heating element (20) to the second heating element (40) characterized in that a monoblock metal heat sink (30) extending between the first and second heating elements (20, 40), over which the second air flow path (f2) passes entirely without deviating from its direction, is comprising a linear first tunnel (T1) and a parallel and spaced linear second tunnel (T2); and a linear upper channel (32) extending between the tunnels (T1 , T2) and through which the second air flow path (f2) passes without deviating from its direction.

2. An induction hob according to claim 1 , wherein the upper channel (32) has a partition wall (322) dividing it in the direction of the second air flow path.

3. An induction hob according to claim 2, wherein the partition wall (322) is singular in the upper channel (32) and divides the upper channel (32) equally along its length into a first channel (K1 ) and a second channel (K2).

4. An induction hob according to claim 3, wherein the widths of the first channel (K1 ) and the second channel (K2) are adjusted to direct the hot air flow caused by the heat generated on the heat sink (30) upward.

5. An induction hob according to any one of the preceding claims, wherein the heat sink (30) is a monolithic structure made of aluminum extrusion.

6. An induction hob according to any one of the preceding claims, wherein the first tunnel (T1 ) and the second tunnel (T2) are arranged adjacent and parallel to the opposite edges of the upper channel (32), respectively.

7. An induction hob according to claim 6, wherein it includes an outwardly adjacent third tunnel (T3) to the second tunnel (T2).

8. An induction hob according to claim 7, wherein a third channel (K3) is provided in the form of an inward recess on an inner edge (36) close to the second tunnel (T2).

9. An induction hob according to claim 8, wherein the third channel (K3) is arranged perpendicular to the third tunnel (T3).

10. An induction hob according to any one of the preceding claims, wherein the heat sink (30) has an inclined extension (35) extending toward its inner wall (36).

11. An induction hob according to any one of the preceding claims, wherein the ventilation opening (14) is provided on the base plate (12) of the housing (10) so that it remains under the air inlet of the fan (50), and includes a deflector plate (64) that pressurizes the air flow by forming a second air flow path (f2) at an angle with the first air flow (f1 ) at the fan’s (50) air outlet, directing the air flow rate radially towards the second heating element (40), and the axial fan (50) power is adjusted to cool the second heating element (40) alone via the second air flow rate (f2).

12. An induction hob according to claim 11 , wherein the fan (50) is an axial fan and the ventilation opening (14) is aligned coaxially with a first coil (24) of the first heating element (20) and the fan (50).

13. An induction hob according to claim 12, wherein a deflector plate (64) is arranged to partially shield the fan (50) outlet from above.

14. An induction hob according to claim 13, wherein from the front edge of the deflector plate (64), a side wall (62) that circumferentially surrounds the impeller (56) of the axial fan (50) and a nozzle-shaped fan outlet (66) arranged to face the second heating element (40) on the side wall (62), covered from above by the deflector plate (64), are included.

15. An induction hob according to claim 14, wherein a diffuser element (70) is positioned in the second air flow path (f2) to distribute the second air flow under the second heating element (40) and adjacent from one end to a front wall (31 ) of the heat sink (30).

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