JP2016051867A - Electronic control device and heat radiation method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the packaging density of an electronic component on a rear surface of a circuit board.SOLUTION: An electronic control device includes: a circuit board 320 in which a plate surface extends in a vertical direction and heating components HE are mounted on its surface; and a metal housing (a body 342 and a cover) for housing the circuit board 320. A protruding part 342G having a lower end part, which has a width gradually narrowing toward the lower side, and protruding toward the circuit board 320 is formed at an upper part of an inner surface of the body 342 which faces a rear surface of the circuit board 320. Further, the heating components HE are mounted on the surface of the circuit board 320 in a portion overlapping with the protruding part 342G. Heat generated by the heating components HE is transmitted to the housing through the protruding part 324G to be radiated therefrom.SELECTED DRAWING: Figure 5

Description

  The present invention relates to an electronic control device and a heat dissipation method thereof.

  An electronic control device mounted on an automobile has a metal casing and a circuit board accommodated in the casing. Heat generating components such as a microcomputer and a semiconductor switching element are mounted on the surface (A surface) of the circuit board. For this reason, as described in JP 2012-69611 A (Patent Document 1), a protruding portion that protrudes from here toward the circuit board on the inner surface of the casing facing the back surface (B surface) of the circuit board. A technique has been proposed in which the heat generated by the heat-generating component is transferred to the housing to dissipate heat.

JP 2012-69611 A

  By the way, in the conventional circuit board, since priority was given to the pattern layout, the heat generating components were scattered and mounted, and the protruding portions of the housing were also scattered. In this case, for the purpose of improving the mounting density of the electronic components on the circuit board, if the electronic components are mounted not only on the front surface but also on the back surface, the electronic components are mounted so as to avoid the scattered protrusions. Must. For this reason, the mounting area of the electronic component on the back surface of the circuit board is reduced, and it is difficult to improve the mounting density of the electronic component.

  Therefore, an object of the present invention is to provide an electronic control device and a heat dissipation method thereof that can improve the mounting density of electronic components on the back surface of a circuit board.

  The electronic control device includes a circuit board on which a heat generating component is mounted on the surface while a plate surface extends in the vertical direction, and a metal housing that houses the circuit board. In addition, a protruding portion that protrudes toward the circuit board is formed on the upper surface of the inner surface of the housing that faces the back surface of the circuit board, and has a lower end that gradually decreases in width toward the lower side. Further, a heat generating component is mounted on the surface of the circuit board at a portion overlapping the protruding portion. Then, the heat generated by the heat generating component is transmitted to the housing through the protruding portion to radiate heat.

  According to the present invention, since the protrusions are not scattered, the mounting density of electronic components on the back surface of the circuit board can be improved.

It is a perspective view which shows an example of the electrically controlled brake unit mounted in the motor vehicle. It is a perspective view which shows the component of an electrically controlled brake unit. It is a perspective view which shows an example of a circuit board. It is a top view which shows an example of the main body which comprises a part of housing | casing. It is a perspective view which shows an example of the arrangement position of the heat-emitting component with respect to the protrusion part of a main body. It is a perspective view which shows an example of the arrangement position of the heat-emitting component with respect to the protrusion part of a main body. It is a top view for demonstrating the effect | action of a protrusion part.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.
1 and 2 show an example of an electrically controlled brake unit mounted on an automobile.

  The electrically controlled brake unit 100 includes a brake master cylinder, a ball screw that applies thrust to the brake master cylinder, and a mechanism unit 200 that incorporates a motor that drives the ball screw, and an electronic control device 300 that controls the motor of the mechanism unit 200. Have. The electrically controlled brake unit 100 is installed in the engine room of the automobile, and when the driver depresses the brake pedal, assists the pedal force and supplies the brake pressure according to the operation amount of the brake pedal to the service brake. To do.

  The mechanical unit 200 is controlled between the electronic control unit 300 and the casing 220 that houses the brake master cylinder, the ball screw, and the motor, the cover 240 that closes the opening 222 of the casing 220 that stores the motor drive components and the like. A socket insert 260 for transmitting and receiving signals and the like. Between the casing 220 and the cover 240, for example, a sealing member such as an O-ring or packing may be interposed so that water or the like does not enter from the gap between them. Here, at least the casing 220 of the casing 220 and the cover 240 can be made of a metal made of an alloy containing aluminum, magnesium, iron, or the like as a main component in order to easily dissipate heat generated by the motor.

  The electronic control device 300 has a substantially rectangular parallelepiped shape, and is disposed on a surface extending in the vertical direction on one side surface of the mechanism unit 200 so as to be installed in a limited space in the engine room. The electronic control device 300 includes a circuit board 320 whose plate surface extends in the vertical direction, and a metal casing 340 that houses the circuit board 320 therein.

  As shown in FIG. 3, a plurality of electronic components EE including a heat generating component HE are mounted on at least the front surface (A surface) and the back surface (B surface) of the circuit board 320. Here, as the heat generating component HE, for example, a semiconductor switching element such as an FET (Field Effect Transistor) of an inverter circuit that drives a motor, a CPU (Central Processing Unit) of a microcomputer, and the like are assumed. In the circuit board 320, heat generated in the heat generating component HE is transferred to the back surface, and therefore a thermal via (not shown) or the like can be formed. In the following description, when it is not necessary to distinguish between the heat generating component HE and the electronic component EE, the heat generating component HE is expressed as the electronic component EE.

  The housing 340 includes a main body 342 that fixes the circuit board 320 and a cover 344 that covers the surface of the circuit board 320 fixed to the main body 342. The main body 342 and the cover 344 are made of an alloy containing aluminum, magnesium, iron, or the like as a main component in order to improve heat dissipation, and are manufactured by casting, pressing, or cutting using a mold.

  As shown in FIG. 4, the main body 342 has a substantially rounded rectangular shape in plan view, and a concave portion 342 </ b> A is formed in the central portion excluding the peripheral portion from one surface to the other surface located on the opposite side. Yes. A circumferential groove 342 </ b> B that fits a part of a seal member 360 such as an O-ring or packing is formed on the peripheral edge of the main body 342 to ensure airtightness with the cover 344. Outside the circumferential groove 342B of the main body 342, a plurality of bolt insertion holes 342C (in the illustrated example) for fastening the main body 342 to the mechanism unit 200 in a detachable manner using a bolt 400 that is an example of a fastening member. 4) formed. Note that a plurality of female screws (not shown) to which the screw portions of the bolts 400 are screwed are formed on the outer surface of the casing 220 of the mechanism unit 200 and at positions corresponding to the bolt insertion holes 342C.

  Openings 342D and 342E for projecting the pin insert 322 and the connector 324 fixed to the back surface of the circuit board 320 to the outside are formed on the bottom surface of the recess 342A of the main body 342, respectively. Here, the pin insert 322 removably connects the pin at the tip thereof to the socket insert 260 of the mechanism unit 200, and the connector 324 transmits and receives a control signal and the like between the circuit board 320 and an external control device. For this purpose, a harness is detachably connected. In addition, a plurality of bosses 342F (9 in the illustrated example) are provided on the bottom surface of the recess 342A of the main body 342 to removably fasten the circuit board 320 to the main body 342 using a male screw 420 which is an example of a fastening member. ) It is erected. Here, a female screw into which a screw portion of the male screw 420 is screwed is formed on the tip surface of the boss 342F. A plurality of insertion holes through which the shaft portion of the male screw 420 is inserted are formed at positions corresponding to the bosses 342F of the circuit board 320.

  Further, the upper part of the concave part 342 of the main body 342, that is, the upper part of the inner surface facing the back surface of the circuit board 320 has a lower end part that gradually decreases in width toward the lower part, and protrudes toward the circuit board 320. One portion 342G is formed. The shape of the lower end portion of the protruding portion 342G can be a staircase shape as shown in the figure, but can also be a sloped shape extending obliquely and linearly. In the illustrated example, the protruding portion 342G is formed in a part of the concave portion 342A in the width direction, but may be formed over the entire width direction. In addition, the area of the front end surface of the protrusion 342G can be an area that can receive the heat generation amount of all the heat generating components HE mounted on the circuit board 320. Further, the protrusion 342G can be integrally formed when the main body 342 is manufactured.

  Here, the tip of the protrusion 342G can be a flat surface in order to increase the heat capacity. Further, the tip of the protrusion 342G and the circuit board 320 may be separated via a predetermined gap, or may be in contact with each other through a sheet having electrical insulation and heat transfer properties. If there is a gap between the tip of the protruding portion 342G and the circuit board 320, for example, the heat transfer efficiency from the circuit board 320 to the protruding portion 342G is improved by interposing a grease having heat transfer properties. be able to.

  The cover 344 has a shape that avoids interference with the electronic component EE of the circuit board 320 fixed to the main body 342, and is fixed to the peripheral surface of the main body 342 by press-fitting, for example. Here, in order to ensure that the cover 344 is fixed to the main body 342, the cover 344 can be fastened using bolts, screws, and the like, which are examples of fastening members. Further, since the cover 344 forms an internal space having airtightness in cooperation with the main body 342, the cover 344 may be manufactured by, for example, pressing a sheet metal or molding a resin in order to reduce the weight. it can.

  Then, the circuit board 320 is fastened and fixed to the main body 342 by the male screw 420, and the cover 344 is press-fitted and fixed to the main body 342 with the seal member 360 interposed between the main body 342 and the cover 344. The electronic control device 300 in which the substrate 320 is accommodated is assembled. In this state, the pin insert 322 and the connector 324 protrude from the back surface of the main body 342 of the electronic control device 300 to the outside. At this time, in order to ensure airtightness between the openings 342D and 342E of the main body 342 and the pin insert 322 and the connector 324, seal members 362 and 364 such as an O-ring and a packing are interposed therebetween. The pin insert 322 and the connector 324 may be airtightly fixed to the main body 342 and detachably connected by a socket insert (not shown) fixed to the back surface of the circuit board 320.

  As shown in FIGS. 5 and 6, the heat generating component HE of the circuit board 320 is mounted below a portion overlapping the protruding portion 342 </ b> G of the main body 342 in plan view. Here, for the purpose of facilitating understanding of the features of the present embodiment, FIG. 5 shows only the heat-generating component HE mounted on the circuit board 320, and FIG. 6 omits the circuit board 320 in addition to this. ing. In this case, the heat generating component HE having a larger amount of heat generation is mounted below the overlapping portion. In this way, the heat generated in the heat generating component HE is transmitted from the back surface of the circuit board 320 to the protruding portion 342G of the main body 342, and then moves upward above the protruding portion 342G as shown in FIG. To do. In short, the heat generated by the heat generating component HE is transmitted to the housing 340 through the protruding portion 342G to be radiated.

  For this reason, the local temperature rise of the circuit board 320 is suppressed, and the electronic component EE can be maintained below the allowable temperature. And the reliability of the electronic control apparatus 300 can be improved by maintaining the electronic component EE below allowable temperature.

  Further, the heat generating component HE of the circuit board 320 can be arranged so that the temperature as a whole becomes uniform in the width direction in consideration of the maximum heat generation amount. In this way, it is possible to prevent the circuit board 320 from locally becoming high temperature and causing, for example, warping.

  Since only one protrusion 342G of the main body 342 is formed on the bottom surface of the concave portion 342A, when the main body 342 is manufactured by casting, the fluidity at the time of casting is improved, and the manufacturability of the main body 342 is improved. Can do.

  Furthermore, a fin for heat radiation that dissipates the heat transmitted upward by the protrusion 342 </ b> G of the main body 342 to the outside can be arranged on the upper portion of the outer surface of the housing 340. In this way, the heat transmitted to the upper part of the main body 342 is radiated to the outside through the fins, so that the heat dissipation performance of the electronic control device 300 can be further improved. In addition, since the fins are located at the upper part of the housing 340, it is possible to efficiently dissipate heat and fluid, and avoid an increase in the size of the fins and suppress an increase in weight.

  The above embodiment is based on the electric control brake unit 100, but can also be applied to other on-vehicle systems such as an engine control system and an automatic transmission control system. Further, the shape of the electronic control device 300 is not limited to a substantially rounded rectangle in a plan view, and may be another shape such as a substantially rounded square in a plan view. Furthermore, the electronic control device 300 can be mounted not only on automobiles but also on industrial equipment, for example.

300 Electronic Control Device 320 Circuit Board 340 Case 342 Main Body 342G Projection 344 Cover HE Heating Component

Claims (5)

A circuit board on which the heat generating component is mounted on the surface while the plate surface extends in the vertical direction;
A metal housing for housing the circuit board;
An electronic control device comprising:
On the upper part of the inner surface of the housing opposite to the back surface of the circuit board, a projecting part that projects toward the circuit board is formed, having a lower end that gradually decreases in width toward the lower side,
The heat generating component is mounted on the surface of the circuit board in a portion overlapping with the protruding portion.
An electronic control device characterized by that. The heat generating component is a part of the surface of the circuit board that is overlapped with the protrusion, and is mounted below the circuit board.
The electronic control device according to claim 1. The heat-generating component is mounted on the lower side as the heat generation amount increases.
The electronic control device according to claim 1 or 2, characterized by the above. In the upper part of the outer surface of the housing, fins for heat dissipation are arranged in a row,
The electronic control device according to any one of claims 1 to 3, wherein A heat dissipation method for an electronic control device comprising: a circuit board on which a heat generating component is mounted on the surface while the plate surface extends in the vertical direction; and a metal housing that houses the circuit board,
A protrusion protruding toward the circuit board is formed at the upper part of the inner surface of the housing facing the back surface of the circuit board, the lower end being gradually narrowed downward, and protruding toward the circuit board. The heat generating component is mounted on the surface of the circuit board that overlaps with
The heat generated in the heat-generating component is transferred to the housing through the protrusion to dissipate heat.
A heat dissipation method for an electronic control device.