Electromagnetic cooker

Abstract

To enhance cooling efficiency of an electromagnetic cooker.SOLUTION: An electromagnetic cooker 1 comprises a casing 2, a front fan 26 that is arranged within the casing 2, and a heat sink 27 that is arranged in the state of facing an outlet 26a of the front fan 26. A plurality of ribs 38 extending along an air flow direction in the outlet 26a are provided on a top surface of the heat sink 27. An upper edge of the rib 38 is inclined to become lower as approaching the outlet 26a.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an induction cooker. [Background technology]

[0002] Patent Document 1 discloses a tabletop induction cooker that includes a thin, box-shaped main body, a top plate placed on the main body to cover the top opening of the main body, and a concentric heating coil placed inside the main body. When electricity is applied to the heating coil, eddy currents are induced in the bottom of a cooking vessel placed on the top plate, causing induction heating in the cooking vessel.

[0003] The main body is provided with a heat dissipation section, a first fan, and a second fan in addition to the heating coil. The main body is provided with a first circulation section for guiding air from the first fan and a second circulation section for guiding air from the second fan. The heating coil is disposed in the first circulation section, and the heat dissipation section is disposed in the second circulation section. The heat dissipation section has a heat sink with a plurality of fins extending in the direction of flow of air discharged from the second fan. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-159038 Summary of the Invention [Problem to be solved by the invention]

[0005] One end of each of the fins faces closely to the outlet of the second fan, and the outlet of the second fan is partially blocked by the fins, which may result in a decrease in airflow and therefore a decrease in cooling efficiency.

[0006] An object of the present invention is to improve the cooling efficiency of an induction cooker. [Means for solving the problem]

[0007] One aspect of the present invention provides an induction cooker comprising a casing, a fan arranged inside the casing, and a heat sink arranged opposite an outlet of the fan, wherein the upper surface of the heat sink is provided with a plurality of ribs extending along the airflow direction at the outlet, and the upper edges of the ribs are inclined so that they become thinner the closer they are to the outlet.

[0008] According to the above configuration, the heat sink faces the outlet of the fan. The air discharged from the fan is blown directly onto the heat sink, which facilitates heat dissipation from the heat sink and, in turn, from heat-generating components that transfer heat to the heat sink. The upper surface of the heat sink is provided with multiple ribs extending in the direction of the airflow at the outlet of the fan. The provision of the ribs increases the surface area of ​​the heat sink, improving the heat dissipation effect. Furthermore, the air blown onto the heat sink is guided by the ribs, allowing it to pass smoothly along the upper surface side of the heat sink. The upper edges of the ribs are lower the closer they are to the outlet of the fan. Because the outlet is not blocked by the ribs, the air volume can be increased, improving cooling efficiency.

[0009] The induction cooker may further include a heating coil arranged inside the casing and a first heat-generating component which is an electronic component constituting a heating circuit that drives the heating coil and generates heat during operation, and the first heat-generating component may be arranged on the upper surface side of the heat sink, downstream of the rib in the airflow direction.

[0010] According to the above configuration, the air guided by the ribs can be blown directly onto the first heat-generating component, improving the cooling efficiency of the first heat-generating component.

[0011] The heat sink may be provided with a ventilation opening that guides air from the upper surface side of the heat sink to the lower surface side of the heat sink, and the ventilation opening may be positioned downstream in the airflow direction from the first heat-generating component.

[0012] According to the above configuration, the air blown onto the first heat-generating component can also flow to the underside of the heat sink through the ventilation holes, preventing the air blown onto the first heat-generating component from stagnating and improving the cooling efficiency of the heat sink and the first heat-generating component.

[0013] The heat sink may have a lower surface supported on the upper surface of the substrate, and a lower protruding portion that protrudes toward the lower surface of the substrate through a notch or a through-hole in the substrate.

[0014] According to the above configuration, the size of the heat sink in the height direction can be increased while the amount of the heat sink protruding above the board can be reduced, thereby achieving both improved heat dissipation efficiency and a thinner induction cooker.

[0015] The bottom surface of the lower protrusion may be smooth.

[0016] With this configuration, the volume of the lower surface of the heat sink is maximized compared to when multiple ribs and grooves are formed between them, which improves the heat absorption efficiency of the heat sink itself and, as a result, the heat dissipation effect.

[0017] The bottom surface of the lower protrusion may be inclined so that the protrusion amount of the lower protrusion decreases toward the outlet.

[0018] According to the above configuration, the outlet is not blocked by the lower protruding portion, so that the air volume can be increased and the cooling efficiency can be improved.

[0019] The induction cooker may further include a second heat-generating component that is an electronic component that constitutes a heating circuit that drives the heating coil and generates heat during operation, and the second heat-generating component may be arranged on the underside of the heat sink and face the outlet.

[0020] According to the above configuration, the air immediately after being discharged from the outlet can be blown directly onto the second heat-generating component, thereby improving the cooling efficiency of the second heat-generating component.

[0021] The air volume from the outlet may not be uniform in the extension direction of the outlet, with the air volume being relatively strong on one side of the extension direction of the outlet and relatively weak on the other side of the extension direction of the outlet, the rib facing the one side of the extension direction of the outlet, and the second heat-generating component facing the other side of the extension direction of the outlet.

[0022] With this configuration, the rib and the first heat-generating component downstream of it in the airflow direction are positioned on the side with the stronger airflow, allowing them to be sufficiently cooled. The second heat-generating component is positioned on the side with the weaker airflow, but faces the outlet, allowing it to be sufficiently cooled as well.

[0023] The induction cooker may further include a heating coil disposed inside the casing, and the heat sink may have a wind-shielding wall that protrudes upward from the edge on the heating coil side.

[0024] This configuration prevents the air, whose temperature has risen due to heat exchange with the heating coil, from being blown directly onto the heat-generating components that transfer heat to the heat sink or onto the heat-dissipating ribs of the heat sink, thereby improving the cooling efficiency of the heat-generating components. [Effects of the Invention]

[0025] According to the present invention, the cooling efficiency of an induction cooker can be improved. [Brief explanation of the drawings]

[0026] [Figure 1] 1 is a perspective view showing an electromagnetic cooker according to an embodiment as viewed from above; [Figure 2] Exploded view of an induction cooker. [Figure 3] FIG. [Figure 4] FIG. 2 is a plan view of the induction cooker with the top plate and upper case removed. [Figure 5] A partial enlarged view of Figure 4. [Figure 6] FIG. [Figure 7] FIG. 2 is a perspective view showing the substrate and the heat sink as viewed from above. [Figure 8] FIG. 2 is a perspective view of the heat sink as viewed from the top side. [Figure 9] FIG. 4 is a perspective view of the heat sink as viewed from the bottom side. [Figure 10] FIG. 4 is a perspective view showing the substrate, the fan, and the heating coil as viewed from the bottom side. DETAILED DESCRIPTION OF THE INVENTION

[0027] Hereinafter, embodiments will be described with reference to the drawings. Note that the same or corresponding elements are designated by the same reference numerals throughout the drawings, and detailed descriptions thereof will be omitted.

[0028] Referring to Figure 1, the induction cooker 1 according to the embodiment is a so-called tabletop type, and is rectangular in plan view. In the following description, the extension direction of one pair of opposite sides of the rectangle is referred to as the width direction W, the extension direction of the other pair of opposite sides is referred to as the depth direction D, and the direction perpendicular to both of these directions is referred to as the height direction H. When the induction cooker 1 is placed horizontally on a table, the width direction W and the depth direction D are oriented horizontally, and the height direction H is oriented vertically.

[0029] An operating unit 9 that is operated by the user is provided on the top surface of the induction cooker 1. The operating unit 9 is located at one end in the depth direction D and is elongated in the width direction W. In the following description, one side in the depth direction D will be referred to as the "front" and the opposite side as the "rear." The "right" is one side in the width direction W, and is the right side of the induction cooker 1 when a user facing the induction cooker 1 from the front looks down on it from above. The "left" is the other side in the width direction W. However, this concept of direction is merely an example and can be changed as appropriate depending on the posture of the induction cooker 1, etc.

[0030] 1 to 4, an induction cooker 1 includes a casing 2, a top plate 3, and a heating coil 4.

[0031] The casing 2 is composed of a lower case 11 and an upper case 12 above the lower case 11. The casing 2 has a rectangular, flat bottom wall 13, a peripheral wall 14 extending upward from the bottom wall 13, an internal space 15 defined by the inner surfaces of the bottom wall 13 and the peripheral wall 14, a flange 16 protruding from the upper end of the peripheral wall 14 toward the inside of the casing 2, and an upper opening 17 defined by the flange 16 and opening the internal space 15 upward.

[0032] The lower case 11 is tray-shaped and includes a bottom wall 13 and peripheral walls 14. The bottom wall 13 is rectangular in plan view, and the peripheral edge of the bottom wall 13 defines the outline of this rectangular shape. The peripheral walls 14 include a front wall 14a extending in the width direction W on the front side, a rear wall 14b extending in the width direction W on the rear side, a right wall 14c extending in the depth direction D on the right side, and a left wall 14d extending in the depth direction D on the left side.

[0033] The upper case 12 forms a flange 16 and defines an upper opening 17. The upper case 12 is fitted from above onto the upper end of the lower case 11, more specifically onto the upper end of the peripheral wall 14. The lower case 11 and the upper case 12 are assembled to each other with bolts 8a that are inserted upward from the lower outer side of the bottom wall 13.

[0034] The top plate 3 is attached to the casing 2 from above so as to close the upper opening 17. The lower surface of the peripheral edge of the top plate 3 is in close contact with the upper surface of the flange 16. The lower surface of the top plate 3, in the portion covering the upper opening 17, defines an internal space 15 together with the bottom wall 13 and the peripheral wall 14.

[0035] The heating coil 4 is housed in the internal space 15. The heating coil 4 is located in the center of the internal space 15 in the depth direction D and width direction W, adjacent to the underside of the top plate 3. A plug receptacle 5 is attached to the rear left corner of the casing 2. A magnetic plug 6a attached to one end of a power cord 6 is removably attached to the plug receptacle 5. When the male plug (not shown) attached to the other end of the power cord 6 is connected to a commercial power source with the magnetic plug 6a attached to the plug receptacle 5, commercial power is input to the plug receptacle 5 via the power cord 6, and the induction cooker 1 becomes operational. Power is supplied to the heating coil 4 through the user's operation of the operating unit 9. This allows induction heating to occur in a cooking container (not shown) placed on the top surface of the top plate 3.

[0036] 2 to 5, the internal space 15 accommodates the heating coil 4 as well as a substrate 20. A heating circuit for applying current to the heating coil 4 to heat the cooking vessel is mounted on the substrate 20. The heating circuit is composed of a wiring pattern printed on the substrate 20 and a number of electronic components mounted on the substrate 20. The electronic components include, for example, a diode bridge 21 that converts AC from a commercial power source to DC, a transistor 22 that adjusts the amount and frequency of the current applied to the heating coil 4, an IC chip 23 that functions as a controller that controls the operation of the transistor 22, and a plurality of capacitors 24 for smoothing or resonance. The transistor 22 is, for example, an IGBT (insulated gate bipolar transistor).

[0037] During operation of the induction cooker 1, the heating coil 4 and several electronic components that make up the heating circuit generate heat. To dissipate heat, the internal space 15 also accommodates a rear fan 25, a front fan 26, and a heat sink 27. This prevents unstable operation of the heating circuit due to heat and prevents deterioration of the electronic components. Examples of electronic components that generate a lot of heat include the diode bridge 21, the transistor 22, and the IC chip 23. An example of an electronic component whose operation may become unstable due to heat is the IC chip 23. An example of an electronic component whose deterioration is accelerated by heat is the capacitor 24 (particularly, an electrolytic capacitor). Note that only the housings of the rear fan 25 and the front fan 26 are shown, and the impellers rotatably supported by the housings are not shown.

[0038] The rear fan 25 and the front fan 26 are arranged close to one side (for example, the right side) in the width direction W, and discharge air to the other side (for example, the left side) in the width direction W. The rear fan 25 is arranged close to the rear side, and the front fan 26 is arranged close to the front side.

[0039] The casing 2 is provided with an intake port 18 for allowing cooling air to flow from the outside of the casing 2 into the internal space 15, and an exhaust port 19 for allowing cooling air to flow from the internal space 15 to the outside of the casing 2. The intake port 18 and the exhaust port 19 are realized by slits that penetrate the casing 2. Each slit has an elongated rectangular shape.

[0040] The air intake 18 is located on the same side in the width direction W as the rear fan 25 and the front fan 26, that is, on the right side in this embodiment. The slits constituting the air intake 18 are provided in almost the entire right wall 14c, the right end of the rear wall 14b, and the right end of the bottom wall 13. The group of slits provided in the bottom wall 13 overlap with the rear fan 25 and the front fan 26 in a plan view. Note that multiple legs are distributed along the bottom of the casing 2, and when the bottom surfaces of the legs are supported on a table, a gap is formed between the outer lower surface of the bottom wall 13 and the table. In other words, when the induction cooker 1 is in use, the air intake 18 provided in the bottom wall 13 is fully open to the space outside and below the casing 2.

[0041] The exhaust port 19 is located downstream, or in this embodiment, on the left side, in the direction of airflow from the rear fan 25 and the front fan 26. Slits that form the exhaust port 19 are provided in almost the entire left wall 14d and in the left end of the front wall 14a.

[0042] The rear fan 25 and the front fan 26 are low-profile blower fans whose axial direction is oriented in the height direction H. The rear fan 25 and the front fan 26 draw air upward from their bottom surfaces and downward from their top surfaces, and discharge the air in a radial direction from their side surfaces. Because blower fans can easily generate high static pressure, they can create a sufficient airflow even in the interior space 15, where ventilation resistance is relatively high due to the dense arrangement of parts to be cooled.

[0043] Inlets for the front fan 26 are provided on the bottom and top surfaces of the front fan 26, respectively, and suck in air below and above the front fan 26. The front fan 26 is supported by the top surfaces of multiple fan support bosses 13a protruding from the inner upper surface of the bottom wall 13, and is fixed to the casing 2 by screwing bolts 8b into the fan support bosses 13a from above. The bottom surface of the front fan 26 is spaced upward from the inner upper surface of the bottom wall 13 by the height of the fan support bosses 13a. The top surface of the front fan 26 is also spaced downward from the lower surface of the top plate 3. The front fan 26 can suck in air through the gap between its bottom surface and the inner upper surface of the bottom wall 13, or through the gap between its top surface and the lower surface of the top plate 3.

[0044] The outlet 26a of the front fan 26 has a low rectangular shape. The short sides of the rectangle are oriented in the height direction H, and the long sides are oriented horizontally. In this embodiment, the outlet 26a of the front fan 26 (particularly its long sides) extends in the depth direction D and opens to the left. The front fan 26 discharges air from its outlet 26a in a horizontal direction that is perpendicular to the extension direction of the outlet 26a. In this embodiment, the airflow direction at the outlet 26a of the front fan 26 is the width direction W, and the downstream side thereof is the left side.

[0045] The rear fan 25 is configured and positioned similarly to the front fan 26. The outlet of the rear fan 25 extends at an angle to the left as it approaches the rear. The rear fan 25 discharges air from its outlet to the front left. The air discharged from the rear fan 25 is blown onto the heating coil 4 located in the center of the interior space 15, and after exchanging heat with the heating coil 4, is discharged to the outside of the casing 2 through the exhaust port 19.

[0046] On the other hand, a heat sink 27 is disposed on the left side of the front fan 26. In other words, the heat sink 27 is disposed opposite the outlet 26a of the front fan 26. Electronic components that generate a large amount of heat are in contact with the heat sink 27, and the heat generated by the electronic components is transferred to the heat sink 27. In this embodiment, as an example of such electronic components, a diode bridge 21 (first electronic component) and a transistor 22 (second electronic component) are attached to the heat sink 27. The air discharged from the front fan 26 is blown directly onto the heat sink 27 and the electronic components in contact therewith, and after exchanging heat with the heat sink 27 and the electronic components, is discharged to the outside of the casing 2 through the exhaust port 19.

[0047] 4 to 6, the substrate 20 is U-shaped in a plan view and is accommodated in the internal space 15 with its thickness direction aligned with the height direction H and the U-shape open to the right. The substrate 20 is supported by the top surfaces of a plurality of substrate support bosses 13b protruding from the inner upper surface of the bottom wall 13, and is fixed to the casing 2 by screwing bolts 8c into the substrate support bosses 13b from above (see FIG. 2). The substrate 20 is accommodated in the internal space 15 in a state where it is slightly floating above the bottom wall 13.

[0048] The substrate 20 has a front extending portion 20a extending rightward on the front side and a rear extending portion 20b extending rightward on the rear side. The heating coil 4 is disposed in the center of the U-shape, i.e., between the front extending portion 20a and the rear extending portion 20b in the depth direction D. The substrate 20 hardly overlaps with the heating coil 4 in a planar view (although a portion of the outer periphery of the substrate 20 may overlap with the substrate 20 in a planar view).

[0049] The substrate 20 does not overlap with the rear fan 25 or the front fan 26 in a plan view. The rear fan 25 is disposed to the right of the rear extension 20b. The front fan 26 is disposed to the right of the front extension 20a. The heat sink 27, the diode bridge 21, and the transistor 22 are attached to the front extension 20a and disposed to the left of the outlet 26a of the front fan 26.

[0050] 6 to 9, heat sink 27 has a substantially rectangular parallelepiped base 31 and a recess 32 continuous with the rear side of base 31. Base 31 and recess 32 integrally form a flat lower surface 30a, which is supported by the upper surface of substrate 20. Base 31 forms an upper surface 30b of heat sink 27 as a whole.

[0051] The upper surface of the recess 32 is positioned below the upper surface 30b of the heat sink 27. The recess 32 protrudes to the right with respect to the base 31. The heat sink 27 has a wind shielding wall 33 that protrudes upward from its rear edge, i.e., the edge on the heating coil 4 side. The heat sink 27 has an opposing wall 34 that protrudes rightward from the rear right part of the base 31 and faces the wind shielding wall 33 in the depth direction D. The recess 32 is surrounded by the wind shielding wall 33 and the opposing wall 34. The wind shielding wall 33 is curved so as to curve rearward as it extends rightward, thereby expanding the dimension of the recess 32 in the depth direction D on the right side.

[0052] The heat sink 27 has a mounting wall 35 that protrudes forward from the upper end of the opposing wall 34. The heat sink 27 has a base 31 and a protruding portion 36 that protrudes to the left of the recess 32. The mounting wall 35 and the protruding portion 36 form a flat upper surface 30b integrally with the base 31. Meanwhile, the lower surfaces of the mounting wall 35 and the protruding portion 36 are located higher than the lower surface 30a that is supported by the substrate 20.

[0053] Therefore, a space 35a is formed between the upper surface of the substrate 20 and the lower surface of the mounting wall 35 on the front surface of the opposing wall 34 (in other words, in front of the right end of the recess 32) and on the front right side of the base 31. The transistor is housed in this space 35a and is screwed to the mounting wall 35 in a state where it is in surface contact with the lower surface of the mounting wall 35 and is floating above the substrate 20.

[0054] That is, the transistor 22 is disposed on the lower surface side of the heat sink 27. The transistor 22 is also attached to the right end portion of the heat sink 27, and therefore faces the outlet 26a of the front fan 26.

[0055] The overhanging portion 36 includes a front overhanging portion 36a that protrudes leftward from the base 31, a rear overhanging portion 36b that extends leftward from the windshield wall 33, and a connecting portion 36c that connects the front overhanging portion 36a and the rear overhanging portion 36b at a position spaced apart to the left of the base 31 and the recess 32. The entire overhanging portion 36 is suspended above the upper surface of the circuit board 20. By providing the overhanging portion 36, an opening that is open both vertically and horizontally is formed between the recess 32 and the connecting portion 36c. As will be described later, this opening functions as a ventilation port 37 that guides a portion of the air that is discharged from the front fan 26 and flows leftward within the recess 32 (i.e., the upper surface side of the heat sink 27) to the lower surface side of the heat sink 27 (more specifically, the lower surface side of the connecting portion 36c).

[0056] The diode bridge 21 is housed in the left end of the recess 32. The diode bridge 21 is screwed into the recess 32 in a state of surface contact with the upper surface of the recess 32. In other words, the diode bridge 21 is disposed on the upper surface side of the heat sink 27.

[0057] A plurality of ribs 38 are provided on the upper surface of the recess 32. The plurality of ribs 38 are arranged at intervals from one another in the depth direction D. Each rib 38 extends in the width direction W between the right end of the recess 32 and the portion where the diode bridge 21 is attached. As described above, the width direction W corresponds to the airflow direction at the outlet 26a of the front fan 26. The front fan 26, ribs 38, diode bridge 21, ventilation opening 37, and connection portion 36c are arranged in this order from the upstream side to the downstream side in the airflow direction.

[0058] The upper edge of each rib 38 is inclined so that the height decreases as it approaches the outlet 26a of the front fan 26. In other words, each rib 38 is in the shape of a right triangle, with the upper edge forming the hypotenuse.

[0059] 6 and 10 , the heat sink 27 has a lower protrusion 39 that protrudes downward from the recess 32. The rear end and left portion of the recess 32, together with the base 31, form a lower surface 30a, and the lower protrusion 39 is provided in the remaining portion of the recess 32. The lower protrusion 39 protrudes downward from the lower surface 30a. The board 20 has a notch 20d so that the lower surface 30a is supported by the upper surface of the board 20 and the lower protrusion 39 is positioned below the upper surface of the board 20. The lower protrusion 39 protrudes toward the lower surface of the board 20 through the notch 20d. As described above, the board 20 is supported by the board support boss 13b, and a sufficient gap is secured between the board 20 and the bottom wall 13 of the casing 2 to provide the lower protrusion 39. In this embodiment, the notch 20d is used to position the lower protrusion 39 on the lower surface side of the substrate 20, but an opening or a through hole may be provided in the substrate 20 instead of the notch 20d.

[0060] While ribs 38 are provided on the upper surface of the recess 32, the bottom surface 39a of the lower protrusion 39 is smooth. The bottom surface 39a of the lower protrusion 39 is inclined so that it protrudes downward from the right end of the recess 32 toward the left (downstream side in the airflow direction). Conversely, the bottom surface 39a of the lower protrusion 39 is inclined so that the protrusion amount of the lower protrusion 39 becomes smaller the closer it is to the outlet 26a.

[0061] In this embodiment, the height of each rib 38 is completely eliminated at the right end of the recess 32. The lower protrusion 39 also completely eliminates its protrusion amount at the right end of the recess 32. Therefore, the right end surface of the heat sink 27 (the surface facing the outlet 26a of the front fan 26) is formed by the recess 32, the windshield wall 33, the opposing wall 34, and the mounting wall 35. The rib 38 and the lower protrusion 39 do not form this right end surface.

[0062] 3, the airflow rate of the front fan 26 has a gradient along the extension direction of the outlet 26a. That is, the airflow rate is not uniform along the extension direction of the outlet 26a. The airflow rate is relatively strong on one side of the extension direction of the outlet 26a and relatively weak on the other side of the extension direction of the outlet 26a. In this embodiment, the extension direction of the outlet 26a is oriented in the depth direction D, and the airflow rate is strong on the rear side and weak on the front side.

[0063] 5 and 7, the recess 32 and the rib 38 provided therein face the rear side (the side with a strong airflow) of the outlet 26a. The mounting wall 35 and the transistor 22 attached thereto face the front side (the side with a weak airflow) of the outlet 26a.

[0064] When the induction cooker 1 configured as described above is in use, the diode bridge 21 and transistor 22 are activated by the passage of current through the heating coil 4, which generates heat. The heat is transferred to the heat sink 27. Meanwhile, the rear fan 25 and front fan 26 are also driven while the induction cooker 1 is in use. The heating coil 4 is cooled by air blown out from the rear fan 25. The windshield prevents air heated by heat exchange with the heating coil 4 from reaching the recess 32. This prevents hot air from being blown directly onto the heat dissipation ribs 38 of the heat sink 27 and the electronic components attached thereto, thereby maintaining high heat dissipation performance of the heat sink 27, as described below.

[0065] The front fan 26 discharges air from its outlet 26a to the left. Part of the air is introduced into the upper surface of the recess 32. The air flows leftward, guided by the upper surface of the recess 32, the ribs 38, the windshield 33, and the opposing wall 34, and passes over the upper surface of the diode bridge 21. In the process, the heat sink 27 and the diode bridge 21 are cooled by the air. The provision of the ribs 38 increases the surface area of ​​the heat sink 27, improving the heat dissipation effect. Part of the air that has passed over the diode bridge 21 passes over the upper surface of the protrusion 36 and flows leftward. Part of the air is also guided to the lower surface of the heat sink 27 through the ventilation openings 37 and flows leftward along the upper surface of the circuit board 20. In the process, the heat sink 27 (particularly its protrusion 36) is cooled by the air.

[0066] The airflow is generated with a relatively large volume, so that the diode bridge 21 is cooled effectively.

[0067] The upper edge of the rib 38 is lower the closer it is to the outlet 26a of the front fan 26. Because the outlet 26a is not blocked by the rib 38, a large volume of air can be introduced to the upper surface side of the recess 32. Furthermore, the presence of the ventilation holes 37 prevents air that reaches the diode bridge 21 from stagnating. This improves the cooling efficiency of the heat sink 27 and the diode bridge 21. Due to the formation of the ventilation holes 37, the heat sink 27 has a protruding portion 36. The volume of the heat sink 27 increases, which increases the amount of heat received from electronic components and improves the heat dissipation effect of the electronic components.

[0068] Furthermore, some of the air discharged from the front fan 26 is introduced into the space below the mounting wall 35. Most of the air introduced into this space is blown onto the transistor 22. Although the air volume is relatively small, the relatively cool air immediately after being discharged from the front fan 26 is blown onto the transistor 22. Therefore, the transistor 22 is also effectively cooled.

[0069] A part of the air introduced into the space is blown onto the right end surface of the base 31 together with the air blown onto the transistor 22. This cools the heat sink 27 (particularly its base 31).

[0070] Furthermore, a portion of the air discharged from the front fan 26 is introduced to the underside of the substrate 20. Part of this air flows to the left along the bottom surface of the lower protrusion 39. Because the bottom surface is smooth, a smooth airflow is formed along the bottom surface. The amount of downward protrusion of the lower protrusion 39 increases as it moves to the left. Therefore, the ventilation resistance of the airflow along the bottom surface increases toward the downstream side in the airflow direction. As a result, part of the air bends to the side of the lower protrusion 39 and flows to the left along the side surface of the lower protrusion 39. This cools the heat sink 27 (particularly the lower protrusion 39).

[0071] In this way, while most of the heat sink 27 is mounted on the upper surface side of the substrate 20, the heat sink 27 also has a downward protrusion 39 that protrudes from the underside of the substrate 20. This makes it possible to increase the volume of the heat sink 27 while reducing the amount of upward protrusion of the heat sink 27 from the substrate 20, thereby achieving both improved cooling efficiency and a thinner induction cooker 1. The arrangement of the downward protrusion 39 makes effective use of the gap between the bottom wall 13 of the casing 2 and the underside of the substrate 20, and does not hinder the induction cooker from being made thinner.

[0072] Like the ribs 38, the lower protrusions 39 are inclined so that the amount of protrusion decreases the closer they are to the outlet 26a, and they face the rear end of the outlet 26a, which has a relatively large air volume. Because the outlet 26a is not blocked by the lower protrusions 39, a large volume of air can be introduced to the underside of the substrate 20, improving cooling efficiency.

[0073] Electronic components such as IC chips are mounted to the left of the heat sink 27. Some of these components protrude below the bottom surface of the substrate 20. Air introduced to the bottom surface of the substrate 20 can effectively cool these electronic components.

[0074] Although the embodiment has been described above, the above configuration is merely an example and can be modified as appropriate within the scope of the present invention. [Explanation of symbols]

[0075] 1 Induction cooker 2 Casing 3 Top Plate 4 heating coils 5 Plug holder 6 Power cord 6a magnetic plug 8a, 8b, 8c bolts 9 Control section 11 Lower case 12 Upper case 13 Bottom wall 13a Fan Support Boss 13b Board support boss 14 Peripheral wall 14a front wall 14b Back wall 14c Right wall 14d left wall 15 Interior Space 16 flange 17 Top opening 18 Air intake 19 Exhaust port 20 PCB 20a Front extension 20b Rear extension 20d notch 21 Diode bridge (first heat generating component) 22 Transistor (second heat generating component) 23 IC chip 24 capacitors 25 Rear Fan 26 Front fan 26a Exit 27 Heatsink 30a Bottom side 30b Top surface 31 Base 32 recess 33 Windshield wall 34 Opposite wall 35 Mounting wall 35a Space 36 Overhang 36a Front overhang 36b Rear overhang 36c connection 37 Ventilation hole 38 Ribs 39 Lower protrusion 39a Bottom

Claims

1. A casing; a fan disposed inside the casing; a heat sink disposed opposite an outlet of the fan; Equipped with a plurality of ribs extending along the airflow direction at the outlet are provided on an upper surface of the heat sink; The upper edge of the rib is inclined so as to become lower as it approaches the outlet. Induction cooker.

2. a heating coil disposed inside the casing; The heating circuit includes an electronic component that drives the heating coil, and further includes a first heat-generating component that generates heat during operation. the first heat generating component is disposed on the upper surface side of the heat sink and downstream of the rib in the airflow direction; The induction cooker according to claim 1.

3. The heat sink is provided with a ventilation hole that guides air from the upper surface side of the heat sink to the lower surface side of the heat sink, The ventilation opening is disposed downstream of the first heat generating component in the airflow direction. The induction cooker according to claim 2.

4. the heat sink has a lower surface supported on the upper surface of the substrate and a lower protruding portion protruding toward the lower surface of the substrate through a notch or a through-hole in the substrate; The electromagnetic cooker according to any one of claims 1 to 3.

5. The bottom surface of the lower protrusion is smooth. The induction cooker according to claim 4.

6. The bottom surface of the lower protrusion is inclined so that the protrusion amount of the lower protrusion becomes smaller as it approaches the outlet. The electromagnetic cooker according to claim 5.

7. The heating circuit includes an electronic component that drives the heating coil, and the second heat-generating component generates heat during operation. the second heat-generating component is disposed on the lower surface side of the heat sink and faces the outlet; The induction cooker according to claim 2.

8. The air volume from the outlet is not uniform in the extension direction of the outlet, and the air volume is relatively strong on one side of the extension direction of the outlet and relatively weak on the other side of the extension direction of the outlet, the rib faces the one side of the outlet in the extending direction, and the second heat-generating component faces the other side of the outlet in the extending direction; The induction cooker according to claim 7.

9. further comprising a heating coil disposed inside the casing; The heat sink has a wind shielding wall that protrudes upward from a peripheral edge on the heating coil side. The induction cooker according to claim 1.

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