Classifications

• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K7/00—Constructional details common to different types of electric apparatus
  • H05K7/20—Modifications to facilitate cooling, ventilating, or heating
  • H05K7/2039—Modifications to facilitate cooling, ventilating, or heating characterised by the heat transfer by conduction from the heat generating element to a dissipating body
  • H05K7/20436—Inner thermal coupling elements in heat dissipating housings, e.g. protrusions or depressions integrally formed in the housing
  • H05K7/2049—Pressing means used to urge contact, e.g. springs
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L23/00—Details of semiconductor or other solid state devices
  • H01L23/34—Arrangements for cooling, heating, ventilating or temperature compensation ; Temperature sensing arrangements
  • H01L23/40—Mountings or securing means for detachable cooling or heating arrangements ; fixed by friction, plugs or springs
  • H01L23/4093—Snap-on arrangements, e.g. clips
• • H—ELECTRICITY
  • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
  • H05K—PRINTED CIRCUITS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS
  • H05K7/00—Constructional details common to different types of electric apparatus
  • H05K7/20—Modifications to facilitate cooling, ventilating, or heating
  • H05K7/20536—Modifications to facilitate cooling, ventilating, or heating for racks or cabinets of standardised dimensions, e.g. electronic racks for aircraft or telecommunication equipment
  • H05K7/20545—Natural convection of gaseous coolant; Heat transfer by conduction from electronic boards
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
  • H01L2924/00—Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
  • H01L2924/0001—Technical content checked by a classifier
  • H01L2924/0002—Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Definitions

• the invention relates to a heat sink for an electric circuit board on which is mounted at least one heat- generating component which requires cooling.
• a circuit board can thus come to include a number of different heat sinks positioned in different places on the circuit board.
• the work of mounting these heat sinks on the respectiv different components is both extensive and expensive.
• the scattered positioning on the circuit board of the heat sinks means that special arrangements are require in order to supply cooling air to the heat sink, which in turn results in difficulties in positioning other electronic components closer to one another on the circuit board.
• the positioning of the heat sinks prevents these circuit boards being positioned near one another
• the aim of the invention is to make possible in a simpler and cheaper manner than known solutions the connection between a heat sink and a circuit board. It is also the aim of the invention to allow a number of circuit boards with heat sinks to be simply mounted in the same housing. These aims are achieved according to the invention by the arrangement being designed with the features which are listed in the characterizing part of the attached claim 1.
• a heat sink which according to the invention is designed with a slot for the one side edge of the circuit board makes it possible for the heat sink to be simply fixed to the circuit board.
• the heat sink being designed with an external mounting flange, simple mounting of the circuit board with the heat sink in conventional mounting tracks is made possible.
• Figure 1 shows a perspective view of a circuit board provided with a heat sink and mounted in mounting tracks.
• Figure 2 shows a horizontal cross sectional view of the circuit board according to Figure 1
• Figure 3 shows in principle a perspective view of how cooling ventilation is achieved around a number of circuit boards which are provided with heat sinks and mounted in a housing.
• FIG 1 shows a per se conventional circuit board 1 on which is mounted a number of electronic components.
• the components 2 which are heat-generating and require cooling are gathered along the one side edge 3 of the circuit board 1.
• a heat sink 4 according to the invention, which extends substantially along the entire side edge 3 of the circuit board 1.
• the heat sink 4 comprises an extruded aluminium profile and has substantially the same cross sectional shape along its entire length.
• the cross sectional shape of the heat sink 4 is shown in Figure 2.
• the heat sink 4 is designed with a slot 5 in which the edge 3 of the circuit board 1 fits and is fixed in a manner which is more closely described later in the description.
• the heat sink 4 is, on the side edge opposite the slot 5, designed with a longitudinal mounting flange 6, which lies in the same plane as the slot 5 and thus also the circuit board 1.
• the width of the flange 6 corresponds to the width of the slot 5, which both correspond to the thickness of the circuit board 1.
• the outer shape of the flange 6 thus corresponds substantially to the shape of the side edge 3 of the circuit board.
• the heat sink 4 is designed along a lower side 7 with a number of longitudinal cooling flanges 8.
• the heat sink 4 comprises three cooling flanges 8, which are designed as double flanges.
• double flanges is meant that each respective cooling flange 8 is in turn designed with a number of smaller cooling flanges 9.
• the heat transferring surf ces of the heat sink 4 are thus larger and the cooling more effective.
• the heat sink 4 is designed along an upper side 10 with a flat surface 11, which is parallel to the plane of the circuit board 1. Bearing against the flat surface 11 is a sheet 12 of a ceramic material, which both is electrically insulating and has good heat transfer properties. Bearing against the sheet 12 under spring pressure are the heat-generating components 2 which are to be cooled.
• the spring pressure is achieved by means of a tensioning element for each component 2, which tensioning element is designed as a spring 13.
• Each spring 13 is of a similar design.
• Each spring 13 comprises a plate spring which is bent at an angle so that two legs 14, 15 are formed.
• the one leg 14 fits and is mountably fixed in a longitudinal slot 16 in the upper side 10 of the heat sink 4.
• the second leg bears resiliently against the respective component 2 and presses it towards the sheet 12. In this manner both the component 2 and the sheet 12 are held in position on the heat sink 4.
• the slot 16 of the heat sink 4 for mounting of such plate springs 13 comprises on the one hand a longitudinal supporting surface 17 and on the other hand a longitudinal supporting heel 18, which are arranged on opposite sides in the slot 16.
• Each plate spring 13 is also designed with a resilient tip 19 which is bent outwards.
• the tip 19 of the spring 13 makes resilient contact with the supporting heel 18, as a result of which a dimensionally stable locking is created which prevents the plate spring 13 being lifted out of the slot 16 again.
• the one leg 14 of the plate spring 13 makes supporting contact with the supporting surface 17.
• the spring 13 is in this connection dimensioned so as to be pressed with suitable force against the component 2 in order to be able to hold it in position. Removal of the spring 13 can if required be simply performed by moving the plate spring 13 sideways in the slot 16 to the end of the slot 16.
• the slot 16 has the same shape along its entire length, it is possible to fix the components 2 with optional positioning along the heat sink 4. This also brings the advantage that identical heat sinks 4 can be used for different circuit boards 1 on which the components 2 have different relative positioning.
• Each component 2 comprises in a per se conventional manner connections 20, which are soldered securely on the circuit board 1. Upon mounting of the components 2 on the heat sink the connections 20 have been bent at an angle.
• Figure 2 shows additionally how the join between the circuit board 1 and the heat sink 4 is arranged.
• the side edge 3 of the circuit board 1 which fits in the slot 5 of the heat sink 4 is designed with a number of, for example four, round holes 21.
• the heat sink 4 has been subjected to a stamping process in which the heat sink 4 has been partially deformed and pressed down into the respective holes 21.
• this stamping process is carried out in such a manner that a tip 22 with an angled edge 23 is pressed into the hole 21.
• the angled edge 23 ensures positioning between the circuit board 1 and the heat sink 4.
• the stamping should be carried out in such a manner that the angled edge 23 is given different orientations in the different holes 21.
• a heat sink 4 designed according to the invention and fixed to a circuit board 1 constitutes a unit which can be simply handled and mounted in a protective housing 24 or similar.
• Such a card 1 can advantageoulsy be fixed in fixed mounting tracks 25, 26 in the housing, which tracks 25, 26 are per se well-known for mounting circuit boards.
• FIG 3 shows a perspective view of how a number of circuit boards 1 can be arranged in a common housing 24.
• the housing 24 may, for example, be intended for mounting in a vehicle and the circuit boards 1 may form part of an electronic unit for control of different functions of the vehicle and its drive engine.
• the housing 24 comprises an inlet 28 for cooling ventilation air and an outlet 29 for removal of the cooling air from the housing 24.
• the circuit boards 1 are arranged parallel to one another and all the circuit boards 1 are mounted on and electrically connected to a so-called mother board 30. This comprises a circuit board which, among other things, supplies voltage to different components on the respective circuit boards 1.
• the mother board 30 is securely screwed in the bottom of the housing and extends perpendicularly in relation to the circuit boards 1.
• the respective heat sinks 4 of the circuit boards 1 are gathered along the same side as the inlet 28 and the housing 24 is moreover designed so that a favourable flow of air is obtained around the respective heat sinks 4.
• the heat sinks 4 are advantageously located nearer the inlet 28 than the outlet 29.
• the air intended for cooling can advantageously be conducted from the ordinary ventilation system of the vehicle (not shown) , in which there is usually access to filtered air with a certain overpressure.
• the ventilation system of the vehicle also includes a compressor-controlled cooling system, it is possible to simply conduct cooled air to the inlet 28 of the housing 24. Similarly, it is possible, when the external temperature is low, to conduct warmed air to the housing 24.
• the temperature in the housing 24 can be kept at approximately the same level irrespective of the external temperature. This also means that the electrical components mounted on the circuit boards 1 have favourable operating conditions.
• a heat sink is fixed along one side of a circuit board. In certain cases, more sides of the circuit board can be provided with heat sinks.
• the mounting tracks 25, 26 in which the circuit boards 1 are mounted do not need to be designed as longitudinal tracks. In alternative embodiments these can be designed as fastening elements which only grip the circuit board and the heat sink along a part of their respective edges.

Landscapes

• Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Microelectronics & Electronic Packaging (AREA)
• Thermal Sciences (AREA)
• Condensed Matter Physics & Semiconductors (AREA)
• General Physics & Mathematics (AREA)
• Computer Hardware Design (AREA)
• Power Engineering (AREA)
• Aviation & Aerospace Engineering (AREA)
• Cooling Or The Like Of Electrical Apparatus (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=20370107

Family Applications (1)

Country Status (5)

Cited By (8)

Families Citing this family (41)

Citations (3)

Family Cites Families (8)

• 1987
  • 1987-11-04 SE SE8704303A patent/SE460008B/sv not_active IP Right Cessation
• 1988
  • 1988-10-21 EP EP88910171A patent/EP0386103A1/en not_active Withdrawn
  • 1988-10-21 JP JP89504596A patent/JPH03502150A/ja active Pending
  • 1988-10-21 US US07/476,375 patent/US5077638A/en not_active Expired - Fee Related
  • 1988-10-21 WO PCT/SE1988/000553 patent/WO1989004593A1/en not_active Application Discontinuation

Patent Citations (3)

Non-Patent Citations (2)

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