Heat sink and vehicle headlight

Abstract

A heat sink (140) for cooling an electronic component of a vehicle headlamp, which has a cooling structure with an outer contour, which, as viewed along an imagined sectional plane, follows a contour curve, which can be described in at least one section by means of a contour function, wherein a fundamental course is formed from a first superposition of a base function and a fundamental function, and the contour function is formed from a second superposition of the fundamental course and a superposition function, wherein the first superposition takes place in that the functional course of the base function forms an axis of a curved coordinate system of the fundamental function, and the second superposition takes place in that the functional course of the fundamental function forms an axis of a curved coordinate system of the superposition function, wherein the base function has a straight, circular or arc-like course, and the fundamental function has a straight or wave-like course, and the superposition function has a wave-like course.

Claims

1. A heat sink (100, 110, 120, 130, 140, 150) for cooling an electronic component of a vehicle headlamp (10), the heat sink (100, 110, 120, 130, 140, 150) comprising: a cooling structure comprising a base (103, 123, 153, 203, 213, 223) on which at least two ribs (101, 111, 121, 131, 141) are arranged, the base having an outer contour, which, as viewed along an imagined sectional plane, follows a contour curve, which can be described in at least one section by means of a contour function (350, 351, 352, 353), wherein a fundamental course is formed from a first superposition of a base function (300, 301, 302, 303) and a fundamental function (310, 311, 312, 313), and the contour function (350, 351, 352, 353) is formed from a second superposition of the fundamental course and a superposition function (330, 331, 332, 333), wherein the first superposition takes place in that the functional course of the base function (300, 301, 302, 303) forms an axis of a curved coordinate system of the fundamental function (310, 311, 312, 313), and the second superposition takes place in that the functional course of the fundamental function (310, 311, 312, 313) forms an axis of a curved coordinate system of the superposition function (330, 331, 332, 333), wherein the base function (300, 301, 302, 303) has a straight course, the fundamental function (310, 311, 312, 313) has a straight course, and the superposition function (330, 331, 332, 333) has a triangular course, wherein the contour function (350, 351, 352, 353) also describes two opposite sides of the outer contour of the heat sink (100, 110, 120, 130, 140, 150), which have a spacing (105, 115, 125, 155, 360, 361) with respect to one another, and the superposition function (330, 331, 332, 333) has a periodic course with a superposition period length (340, 341, 342, 343), and wherein the superposition period length is at most a third as long as the spacing.

2. The heat sink (100, 110, 120, 130, 140, 150) according to claim 1, wherein the fundamental function (310, 311, 312, 313) has a periodic course with a fundamental period length (320, 321, 322, 323) and the superposition function (330, 331, 332, 333) has a periodic course with a superposition period length (340, 341, 342, 343), wherein the fundamental period length (320, 321, 322, 323) is at least five-times as long as the superposition period length (340, 341, 342, 343).

3. The heat sink (100, 110, 120, 130, 140, 150) according to claim 1, wherein the fundamental function (310, 311, 312, 313) and the superposition function (330, 331, 332, 333) run differently in each case, either in a wave-like manner, from the value of wave-like or triangular.

4. A vehicle headlamp (10), comprising: a lamp (11) and/or power electronics (12) and an optical system (13); and the heat sink (100, 110, 120, 130, 140, 150) according to claim 1, wherein the lamp (11) and/or the power electronics (12) is/are thermally coupled to the heat sink (100, 110, 120, 130, 140, 150).

5. The heat sink according to claim 1, wherein the functional course of the base function (300, 301, 302, 303) forms an axis of a curved, orthogonal coordinate system of the fundamental function (310, 311, 312, 313), and the functional course of the fundamental function (310, 311, 312, 313) forms an axis of a curved, orthogonal coordinate system of the superposition function (330, 331, 332, 333).

6. The heat sink according to claim 1, wherein the contour function (350, 351, 352, 353) describes two opposite sides of the outer contour of ribs (101, 111, 121, 131, 141) or pins (152) of the heat sink (100, 110, 120, 130, 140, 150), which have a spacing (105, 115, 125, 155, 360, 361) with respect to one another.

7. The heat sink according to claim 1, wherein the superposition period length (340, 341, 342, 343) is at most half as long as the spacing (105, 115, 125, 155, 360, 361).

8. The heat sink according to claim 1, wherein the superposition period length (340, 341, 342, 343) is at most a third as long as the spacing (105, 115, 125, 155, 360, 361).

9. The heat sink according to claim 2, wherein the fundamental period length (320, 321, 322, 323) is at least ten-times as long as the superposition period length (340, 341, 342, 343).

Description

(1) The invention and the advantages thereof are described in more detail hereinafter on the basis of non-limiting exemplary embodiments, which are illustrated in the attached drawings. In the drawings

(2) FIG. 1 shows a perspective view of a heat sink according to the prior art, having ribs and a smooth surface,

(3) FIG. 1a shows the heat sink according to FIG. 1 in a view from the front,

(4) FIG. 1b shows a cutout of the heat sink in a horizontal sectional plane A-A according to FIG. 1a,

(5) FIG. 2 shows a perspective view of a heat sink according to the prior art, having ribs and a corrugated surface,

(6) FIG. 2a shows the heat sink according to FIG. 2 in a view from the front,

(7) FIG. 2b shows a cutout of the heat sink in a horizontal sectional plane B-B according to FIG. 2a,

(8) FIG. 3 shows a perspective view of a first embodiment of a heat sink according to the invention, having ribs and a corrugated surface,

(9) FIG. 3a shows the heat sink according to FIG. 3 in a view from the front,

(10) FIG. 3b shows a cutout of the heat sink in a horizontal sectional plane C-C according to FIG. 3a,

(11) FIG. 3c shows a cutout of second embodiment of a heat sink according to the invention in a horizontal sectional plane according to FIG. 3a,

(12) FIG. 4 shows a perspective view of a third embodiment of a heat sink according to the invention, having ribs and a corrugated surface,

(13) FIG. 4a shows the heat sink according to FIG. 4 in a view from the front,

(14) FIG. 4b shows a cutout of the heat sink in a horizontal sectional plane D-D according to FIG. 4a,

(15) FIG. 4c shows a cutout of a fourth embodiment of the heat sink in a horizontal sectional plane,

(16) FIG. 4d shows a cutout of a fifth embodiment of the heat sink in a horizontal sectional plane,

(17) FIG. 4e shows a fundamental function and a superposition function of the heat sink according to FIG. 4c,

(18) FIG. 4f shows a fundamental function and a superposition function of the heat sink according to FIG. 4d,

(19) FIG. 5 shows a perspective view of a heat sink according to the prior art, having pins and a smooth surface,

(20) FIG. 5a shows the heat sink according to FIG. 5 in a view from the front,

(21) FIG. 5b shows a cutout of the heat sink in a horizontal sectional plane E-E according to FIG. 5 in a view from above,

(22) FIG. 6 shows a perspective view of a sixth embodiment of a heat sink according to the invention, having pins and a corrugated surface,

(23) FIG. 6a shows the heat sink according to FIG. 6 in a view from the front,

(24) FIG. 6b shows a cutout of the heat sink in a horizontal sectional plane F-F according to FIG. 6 in a view from above,

(25) FIG. 7 shows a symbolically illustrated vehicle headlamp, which comprises a heat sink according to the invention.

(26) Exemplary embodiments of the invention are now explained in more detail with reference to FIG. 1 to FIG. 7. In particular, important parts for the invention in a headlamp are illustrated, wherein it is clear that a headlamp also contains many other parts, which are not shown, which allow a sensible use in a motor vehicle, such as a passenger car, motorcycle or lorry in particular. Therefore, electronics, further optical elements, mechanical adjustment devices or holders are for example not shown for the sake of clarity.

(27) In further context, an outer contour of a heat sink means the shaping of the surface of the heat sink.

(28) Typically, a heat sink is produced from a metal, for example aluminium, which is shaped by means of a forming method, such as e.g. extrusion, a casting method such as high-pressure die casting or injection moulding or a CNC milling method. Alternatively, production by means of a 3D metal printing method is conceivable.

(29) For example, the power loss of an electronic component, particularly a power electronics component such as an LED or a power transistor, leads to heat. This must be dissipated in order to prevent functional impairment and possible destruction of the component. Heat sinks, which are in thermal contact with this heat source, improve the dissipation of the heat. Often, heat sinks comprise cooling ribs, in order to enlarge the surface area of the heat sink and improve the efficiency thereof. For a beneficial convection flow on the surface of the heat sink, it is advantageous if the heat sink is arranged with cooling ribs in an installation position, for example in a vehicle headlamp, in such a manner that cooling ribs are orientated vertically.

(30) FIG. 1 shows a heat sink 200 with ribs 201 and a base 203 according to the prior art. In FIG. 1a, the heat sink 200 is shown in a side view. FIG. 1b shows a cutout, or a cooling rib 201 of the heat sink 200 in a sectional view according to the horizontal sectional plane A-A of FIG. 1a, wherein a smooth outer contour of the surface and the thickness or the spacing 205 of the opposite outer surfaces of the rib 201 of the heat sink 200 can be seen.

(31) FIG. 2 shows a heat sink 210 with ribs 211 and a base 213 according to the prior art. In FIG. 2a, the heat sink 210 is shown in a side view. FIG. 2b shows a cutout, or a cooling rib 211 of the heat sink 210 in a sectional view according to the horizontal sectional plane B-B of FIG. 2a, wherein a corrugated outer contour of the surface and the thickness or the spacing 215 of the opposite outer surfaces of the rib 211 of the heat sink 210 can be seen.

(32) FIG. 3 shows a heat sink 100 according to the invention with ribs 101 and a base 103. In FIG. 3a, the heat sink 100 is shown in a side view. FIG. 3b shows a cutout or a cooling rib 101 of the heat sink 100 in a sectional view according to the sectional plane C-C of FIG. 3a, wherein a triangular outer contour of the heat sink 100 can be seen, wherein the outer contour is formed from a superposition of a straight base function, a straight fundamental function and a triangular superposition function, wherein the triangular function has rounded corners, as can be seen in the figure.

(33) The heat sink 100 is suitable for cooling an electronic component of a vehicle headlamp. An intersecting curve, which describes the outer contour of the heat sink 100, lies in a sectional plane C-C according to FIG. 3a of the heat sink 100.

(34) The heat sink 100 has a cooling structure with an outer contour, which, as viewed along an imagined sectional plane, follows a contour curve, which can be described in at least one section by means of a contour function.

(35) A fundamental course is formed from a first superposition of a base function and a fundamental function. The contour function is formed from a second superposition of the fundamental course and a superposition function.

(36) The first superposition takes place in that the functional course of the base function forms an axis of a curved, here orthogonal, coordinate system of the fundamental function. The second superposition takes place in that the functional course of the fundamental function forms an axis of a curved, here orthogonal, coordinate system of the superposition function.

(37) The base function has a straight, circular or arc-like course. The fundamental function has a straight or wave-like course. The superposition function has a wave-like course.

(38) A wave-like course may for example mean a course, which can be described by a sine function, the value of a sine function, a triangular function, a sawtooth function or by a periodic semicircle function. Other periodic functions are also possible, particularly those which correspond to the value of a periodically running function.

(39) Exemplary embodiments of the base functions 300, 301, 302, 303, the fundamental functions 310, 311, 312, 313 and the superposition functions 330, 331 332, 333 and the resulting contour functions 350, 351, 352, 353 are shown in FIGS. 4e and 4f. However, it is to be considered that the contour functions 350, 351, 352, 353 shown are only used for fundamental illustration and are not the mathematically exact implementation of the superpositions of the shown base functions 300, 301, 302, 303, the fundamental functions 310, 311, 312, 313 and the superposition functions 330, 331 332, 333.

(40) The heat sink 100 illustrated in FIG. 3 has a base 103, on which at least two ribs 101 are arranged, which are orientated substantially parallel to one another. The base 103 is used for contacting a heat source, which should be cooled by means of the heat sink 100.

(41) In FIG. 3, two geometric centre lines 106, 107 are shown, of two adjacent cooling ribs 101, which run in a horizontal plane, for example in the sectional plane C-C according to FIG. 3a, in the direction of the longitudinal extent of the cooling rib, which enclose a horizontal angle 108, 109 with respect to the horizontal centre line 106, 107, which is smaller than 10°, preferably smaller than 5° and particularly preferably smaller than 1°. The centre line 106 is indicated in FIG. 3b and the centre line 116 is indicated in FIG. 3c.

(42) The parallel arrangement of the cooling ribs 101 of the heat sink 100 may result from a forming method such as extrusion or a casting method such as high-pressure die casting. It is advantageous however, if the surfaces of the ribs run parallel (with a respectively equal angle 108, 109 of 0° in each case) or at a small angle 108, 109 (smaller than 10°) of the ribs with respect to one another, as a convection flow of rising warm air is also improved as a result.

(43) The ribs 101, starting from the side on which they are connected to one another via the base 103, taper in their cross section along the elevation of the ribs 101 to the open end 104 thereof.

(44) The contour function 350 describes two opposite sides of the outer contour of a cooling rib of the heat sink 100, wherein the sides have a spacing 105 from one another. The superposition function has a periodic course with a superposition period length, wherein the superposition period length is preferably at most half as long, particularly preferably at most a third as long, as the spacing 105.

(45) In this context, the spacing 105 is for example formed by a minimum spacing 105min, a maximum spacing 105max or an average spacing.

(46) FIG. 3c shows a second embodiment of the invention in the form of a heat sink 110, having a cooling rib 111 in a horizontal sectional plane (not shown), which corresponds to that of the sectional plane C-C according to FIG. 3a, wherein a triangular outer contour of the surface of the cooling rib 111 of the heat sink 110 can be seen, and wherein the triangular outer contours (with rounded corners) of the surface of the cooling rib 111 of the heat sink 110 on two opposite sides of the cooling rib 111 of the heat sink 110 are phase-shifted with respect to those according to FIG. 3b. Here, the maxima of the superposition function of the heat sink 110 lie in-phase, whilst the maxima of the heat sink 100 are arranged in a contrary manner. In addition, the spacing 115 of the opposite outer surfaces of the ribs 111 can be seen. The superpositions of the base, fundamental and superposition function are the same as or similar to the example from FIG. 3b.

(47) FIG. 4 shows a third example in the form of a heat sink 120 with ribs 121, the open ends 124 thereof and a base 123. In FIG. 4a, the heat sink 120 is shown in a side view. FIG. 4b shows a cutout of the heat sink 120 in a sectional view according to the horizontal sectional plane D-D according to FIG. 4a, wherein a corrugated outer contour of the surface of a cooling rib 121 of the heat sink 120 according to the invention can be seen.

(48) In the sectional plane D-D of the heat sink 120, a form of the intersecting curve can be seen, which is at least partially formed from a superposition of a substantially straight or substantially circular base function and a straight, a wave-like or a triangular fundamental function and a wave-like or the value of a wave-like superposition function.

(49) The superposition is defined in that the functional course of the base function forms an axis of a curved, preferably orthogonal coordinate system of the fundamental function at least in certain sections, and the functional course of the fundamental function forms an axis of a curved, preferably orthogonal coordinate system of the superposition function at least in certain sections.

(50) The heat sink 100 is formed from at least two ribs 101, which are arranged substantially parallel to one another and are connected to one another on a pin side by means of a base 103.

(51) The ribs 121, starting from the side on which they are connected to one another via the base 123, taper in their cross section along the elevation of the ribs 121 to the open end 124 thereof.

(52) The ribs 121 between opposite parts of the outer contour have a spacing 125. The superposition function has a periodic course with a superposition period length, wherein the superposition period length is preferably at most half as long, particularly preferably at most a third as long, as the spacing 125.

(53) In this context, the spacing 125 is for example formed by a minimum spacing, a maximum spacing or an average spacing.

(54) FIG. 4c shows a fourth example in the form of a heat sink 130 with ribs 131, a spacing 360 and a base, which is constructed analogously to the preceding embodiments. The sectional image shown corresponds to a sectional plane which is placed in accordance with that of the sectional plane D-D according to FIG. 4a. Details about the surface design of the heat sink 130 in connection with a fundamental function 310 are to be drawn when viewed together with FIG. 4e, as is explained further below.

(55) In a horizontal sectional plane (not shown) of the heat sink 130, a form of the intersecting curve can be seen, which is at least partially formed from a superposition of a substantially straight or substantially circular base function and a straight, a wave-like or a triangular fundamental function 310 and 311 and a wave-like or the value of a wave-like superposition function 330 and 331.

(56) The superposition is defined in that the functional course of the base function 300 and 301 forms an axis of a curved, preferably orthogonal coordinate system of the fundamental function 310 and 311 at least in certain sections, and the functional course of the fundamental function 310 and 311 forms an axis of a curved, preferably orthogonal coordinate system of the superposition function 330 and 331 at least in certain sections.

(57) In this example, the axis of the coordinate system of the base function 300 and 301 runs straight and the coordinate system of the base function 300 and 301 is orthogonal in origin.

(58) Likewise, the axis of the coordinate system of the fundamental function 310 and 311 runs straight and the coordinate system of the fundamental function 310 and 311 is orthogonal in origin.

(59) The base functions 300 and 301 have a spacing 360.

(60) The fundamental function 310 and 311 has a periodic course with a fundamental period length 320 and 321.

(61) The superposition function 330 and 331 has a periodic course with a superposition period length 340 and 341, wherein the superposition period length 340 and 341 is preferably at most half as long, particularly preferably at most a third as long, as the spacing 360.

(62) The fundamental period length 320 and 321 is at least preferably five-times as long, particularly preferably ten-times as long as the superposition period length 340 and 341.

(63) In this context, the spacing 360 is for example formed by a minimum spacing, a maximum spacing or an average spacing.

(64) FIG. 4d shows a fifth example in the form of a heat sink 140 with ribs 141 and a base, which is constructed analogously to the preceding embodiments. The sectional image shown corresponds to a sectional plane which is placed in accordance with that of the sectional plane D-D according to FIG. 4a. Details about the surface design of the heat sink 140 in connection with a fundamental function 312 are to be drawn when viewed together with FIG. 4f, as is explained further below.

(65) In a horizontal sectional plane (not shown) of the heat sink 140, a form of the intersecting curve can be seen, which is at least partially formed from a superposition of a substantially straight or substantially circular base function and a straight, a wave-like or a triangular fundamental function 312 and 313 and a wave-like or the value of a wave-like superposition function 332 and 333.

(66) The superposition is defined in that the functional course of the base function 302 and 303 forms an axis of a curved, preferably orthogonal coordinate system of the fundamental function 312 and 313 at least in certain sections, and the functional course of the fundamental function 312 and 313 forms an axis of a curved, preferably orthogonal coordinate system of the superposition function 332 and 333 at least in certain sections.

(67) In this example, the axis of the coordinate system of the base function 302 and 303 runs straight and the coordinate system of the base function 302 and 303 is orthogonal in origin.

(68) Likewise, the axis of the coordinate system of the fundamental function 312 and 313 runs straight and the coordinate system of the fundamental function 312 and 313 is orthogonal in origin.

(69) The base functions 302 and 303 have a spacing 361.

(70) The fundamental function 312 and 313 has a periodic course with a fundamental period length 322 and 323.

(71) The superposition function 332 and 333 has a periodic course with a superposition period length 342 and 343, wherein the superposition period length 342 and 343 is preferably at most half as long, particularly preferably at most a third as long, as the spacing 361.

(72) The fundamental period length 322 and 323 is at least preferably five-times as long, particularly preferably ten-times as long as the superposition period length 342 and 343.

(73) In this context, the spacing 361 is for example formed by a minimum spacing, a maximum spacing or an average spacing.

(74) The triangular fundamental function 312 and 313, and the wave-like superposition function 332 and 333 run differently from their form in each case.

(75) FIG. 5 shows a heat sink 220 with pins 222, the open ends 224 thereof and a base 223 according to the prior art. In FIG. 5a, the heat sink 220 is shown in a side view. FIG. 5b shows a cutout of the heat sink 220 in a sectional view according to the horizontal sectional plane E-E according to FIG. 5a, wherein a smooth outer contour of the surface and a spacing or diameter 225 of a pin 222 of the heat sink 220 can be seen.

(76) FIG. 6 shows a heat sink 150 according to the invention, having pins 152, the open ends 154 thereof and a base 153. In FIG. 6a, the heat sink 150 is shown in a side view. FIG. 6b shows a cutout of the heat sink 150 in a sectional view according to the horizontal sectional plane F-F according to FIG. 6a, wherein a corrugated or triangular outer contour (with rounded corners) of the surface of the heat sink 150 according to the invention can be seen.

(77) The pins 152, starting from the side on which they are connected to one another via the base 153, taper in their cross section along the elevation of the pins 152 to the open end 154 thereof.

(78) The pins 152 have a diameter or a spacing 155 between opposite parts of their outer contour. In this context, the spacing 155 is for example formed by a minimum spacing, a maximum spacing or an average spacing.

(79) A vehicle headlamp 10 is illustrated symbolically in FIG. 7, which comprises a lamp 11, power electronics 12, heat sink 100 and an optical system 13.

(80) The lamp 11 is for example formed from one or more LEDs or laser diodes. The power electronics 12 for example contain driving transistors for LEDs as lamps 11.

(81) The lamp 11 and the power electronics 12 are preferably connected via a contact element 14, for example a mica washer or a mass of thermal compound which improves the thermal resistance and as a result ensures a good thermal coupling of the heat source to the heat sink, to a heat sink 100 according to the invention.

(82) The optical system 13 may comprise one or more optical elements, for example in the form of lenses, apertures or transparent covers.

REFERENCE LIST

(83) 100, 110, 120, 130, 140, 150, 200, 210, 220 Heat sink 101, 111, 121, 131, 141, 152, 201, 211, 222 Rib or pin of the heat sink 103, 123, 153, 203, 213, 223 Base of the heat sink 104, 124, 154 Open end of the rib or the pin 105, 105min, 105max, 115, 125, 155, 205, 215, 225, 360, 361 Spacing 106, 107, 116 Centre line 108, 109 Angle 300, 301, 302, 303 Base function 310, 311, 312, 313 Fundamental function 320, 321, 322, 323 Fundamental period length 330, 331, 332, 333 Superposition function 340, 341, 342, 343 Superposition period length 350, 351, 352, 353 Contour function 10 Vehicle headlamp 11 Lamp 12 Power electronics 13 Optical system 14 Contact element 15 Light ray