Electronic control unit and method of manufacturing the same

Abstract

An electronic control unit is disclosed. The electronic control unit includes: a resin board; a power device that is surface-mounted on the resin board; a microcomputer that is configured to control the power device; first heat radiation means for radiating heat, the first heat radiation means being disposed on an opposite side of the resin board from the power device; and first heat conduction means for conducting the heat generated by the power device to the first heat radiation means.

1 . An electronic control unit comprising:
 a resin board;   a power device that is surface-mounted on the resin board;   a microcomputer that is configured to control the power device;   first heat radiation means for radiating heat, the first heat radiation means being disposed on an opposite side of the resin board from the power device; and   first heat conduction means for conducting the heat generated by the power device to the first heat radiation means.   
     
     
         2 . The electronic control unit according to  claim 1 , wherein:
 the first heat conduction means includes at least one of an insulating heat-radiation sheet and a heat radiation grease.   
     
     
         3 . The electronic control unit according to  claim 1 , wherein:
 the resin board has an opening;   the first heat conduction means is disposed in the opening of the resin board; and   the first heat conduction means is in direct connect with the power device and the first heat radiation means.   
     
     
         4 . The electronic control unit according to  claim 1 , further comprising:
 second heat radiation means for radiating the heat generated by the power device, the second heat radiation means being disposed on an opposite side of the power device from the resin board; and   second heat conduction means for conducting the heat generated by the power device to the second heat radiation means.   
     
     
         5 . The electronic control unit according to  claim 4 , wherein:
 the second heat conduction means includes at least one of a heat radiation grease and a small-hardness insulating heat radiation sheet; and   the at least one of the heat radiation grease and the small-hardness insulating heat-radiation sheet is disposed between the second heat radiation means and the power device.   
     
     
         6 . The electronic control unit according to  claim 1 , further comprising:
 heat conduction path means for providing a heat conduction path in an inside of the resin board,   wherein the heat conduction path conducts the heat generated by the power device.   
     
     
         7 . The electronic control unit according to  claim 6 , wherein:
 the heat conduction path means includes a through-hole via of the resin board; and   the through-hole via penetrates the resin board in a thickness direction of the resin board, and is located directly below the power device.   
     
     
         8 . The electronic control unit according to  claim 7 , wherein
 the first heat conduction means includes the heat radiation grease; and   the through-hole via is filled with the heat radiation grease.   
     
     
         9 . The electronic control unit according to  claim 7 , wherein:
 the heat conduction path means further includes a heat conduction layer; and   the heat conduction layer is connected with an outer wall of the through-hole via and extends in an extension direction of the resin board.   
     
     
         10 . The electronic control unit according to  claim 9 , wherein:
 the heat conduction layer is connected with a screw that fixes the resin board and the first heat radiation means.   
     
     
         11 . The electronic control unit according to  claim 9 , further comprising:
 a heat conduction chip that is disposed on the resin board,   wherein:   the heat conduction chip has a first end and a second end;   the first end of the heat conduction chip is connected with the heat conduction layer; and   the second end of the heat conduction chip is protruded from a surface of the resin board in the thickness direction of the resin board.   
     
     
         12 . The electronic control unit according to  claim 11 , wherein:
 the first heat conduction means includes a heat radiation grease that fills a space between the heat conduction chip and the first heat radiation means.   
     
     
         13 . The electronic control unit according to  claim 11 , wherein:
 the second heat conduction means includes a heat radiation grease that fills a space between the heat conduction chip and the second heat radiation means.   
     
     
         14 . The electronic control unit according to  claim 1 , wherein:
 the resin board has a concave depression that is disposed on a same side of the resin board as the first heat radiation means is;   the first heat conduction means includes the heat radiation grease; and   the concave depression of the resin board is filled with the heat radiation grease.   
     
     
         15 . The electronic control unit according to  claim 4 , wherein:
 the second heat radiation means includes a cover constructed to protect the power device;   the first heat radiation means includes a heat sink; and   the cover is connected with an end of the heat sink.   
     
     
         16 . The electronic control unit according to  claim 15  wherein:
 the cover is connected with the end of the heat sink by snap-fitting.   
     
     
         17 . The electronic control unit according to  claim 15 , wherein:
 the electronic control unit is a component of an electric power-assisted steering system equipped in a vehicle; and   the cover, the heat sink and a body of the vehicle are tighten together by using a screw.   
     
     
         18 . The electronic control unit according to  claim 15 , wherein
 the cover, the resin board and the heat sink are tighten together by using a screw.   
     
     
         19 . The electronic control unit according to  claim 4 , further comprising:
 a heat generating component mounted on the resin board,   wherein the second heat radiation means is disposed on an opposite side of the heat generating component from the resin board.   
     
     
         20 . A method of manufacturing an electronic control unit, comprising:
 mounting an electronic component on a surface of a resin board, the electronic component including a power device;   testing an operating condition of the electronic component at a predetermined high temperature or a predetermined low temperature after mounting the electronic component on the surface of the resin board, wherein the predetermined low temperature is lower than the predetermined high temperature; and   providing heat conduction means and heat radiation means on an opposite side of the resin board from the power device after testing the operating condition of the electronic component.