JP2016157715A - Heat dissipation substrate and heat dissipation case housing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat dissipation substrate for mounting an electronic component, in which improvement of heat dissipation is achieved by a relatively simple structure at a low cost, and to provide a heat dissipation case for housing the same.SOLUTION: By a heat dissipation substrate provided with one or a plurality of interlayer heat transmission layers 330, on an inside layer of a multilayer substrate for mounting an electronic component EC, the heat generated from the electronic component EC via the interlayer heat transmission layers 330 can be discharged to the outside while equalizing on the heat dissipation substrate. Furthermore, a heat dissipation case 400 is constituted by connecting the heat dissipation substrate, provided with an extension 335 at the peripheral edge of the interlayer heat transmission layers 330 and an opening from the plate surface of the substrate to the interlayer heat transmission layers 330, with the extension 335, and connecting with the interlayer heat transmission layers 330 in the opening by a heat transmission protrusion.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a substrate on which an exothermic electronic component is mounted, and more specifically, by providing an interlayer heat transfer layer inside the substrate, heat generated from the exothermic electronic component is transferred to the interlayer of the substrate. The present invention relates to a heat dissipation substrate that can be discharged to the outside through a heat transfer layer and a heat dissipation case that accommodates the heat dissipation substrate.

  2. Description of the Related Art Conventionally, for high-tech industrial products such as automobiles, with the development of industrial technology related to these, there is an increasing demand for downsizing of devices used for the technical industrial products. In response to these requests, electronic components used in technical industrial products such as automobiles and substrates used in various control devices are required to have higher integration and higher capacity.

  And, in the high integration and high capacity of the electronic parts used in the technical industrial products as described above and the substrates used in various control devices of the technical industrial products, these technologies are compared with the general home appliances. Industrial products have special characteristics such as high vibrations and often used in high-temperature environments, so it is necessary to ensure high reliability from the viewpoint of improving the safety of equipment. It has become.

  Of the issues for ensuring high reliability, one of the most important issues is the problem of heat dissipation of the device.

  That is, in an electronic circuit using an electronic component such as a power semiconductor that handles a large amount of power, such as an inverter circuit or a power supply circuit, the circuit board becomes high temperature, and such heat generation reduces the function of the electronic component. May cause malfunction.

  For example, there are defects such as defective insulation due to damage caused by thermal deformation of a substrate made of ceramic or the like, and malfunction of electronic components due to occurrence of cracks in the solder joint surface.

  For this reason, high efficiency from the substrate on which the electronic component is mounted is intended to enable the heat generated from each highly integrated and high capacity electronic component to be released quickly and smoothly to the outside. Development of new heat dissipation technology has been required.

  As an example of a heat dissipation technique from such a substrate, for example, a technique described in Japanese Unexamined Patent Application Publication No. 2007-96252 (Patent Document 1) is disclosed.

  The technique disclosed in the above-mentioned patent document 1 is a connection structure that ensures waterproofness and does not cause the insulating substrate to be cracked, stably reduces thermal resistance, downsizes an inverter that constitutes a power module, etc., and insulates power elements. An object of the present invention is to provide a structure in which a substrate is miniaturized and easily assembled.

  For this reason, in the technique disclosed in Patent Document 1, a wiring board in which a wiring conductor is formed on an insulating substrate is bonded to a heat dissipation board in which a groove for flowing a coolant on the main surface is formed so as to close the groove. In the liquid-cooled circuit board formed as described above, a structure is proposed in which a wiring conductor having an edge along the groove is formed in a plan view and the edge along the groove of the wiring conductor is positioned inside the groove.

  Moreover, as an example of another heat dissipation technique, for example, a technique described in Japanese Patent Application Laid-Open No. 2012-99782 (Patent Document 2) is disclosed.

  The technology disclosed in Patent Document 2 provides a high-power metal substrate by increasing the integration and capacity of electronic components by using an improved heat dissipation function of a base made of aluminum (Al) and copper (Cu). It is an object to provide a heat dissipation board that can be used.

  Therefore, in the technique disclosed in Patent Document 2, a copper layer having a certain thickness, an anodized insulating layer provided on the upper and lower surfaces of the copper layer, and an aluminum layer provided between the copper layer and the anodized insulating layer are further provided. A heat dissipation substrate having a structure including the above is disclosed.

JP 2007-96252 A JP 2012-99782 A

  However, in the structure described in Patent Document 1, the weight increases as the substrate becomes thicker, and further, a circulation path for circulating the cooling liquid is formed, and then the cooling liquid is pumped into the circulation path. Since the structure needs to be circulated, the structure is complicated, resulting in a disadvantage in cost.

  In the technique described in Patent Document 2, copper having different thermal conductivity and upper and lower aluminum layers are used as essential components, and the heat dissipation characteristics are determined in advance by designing the thickness of each layer. Therefore, there is a drawback that the structure is complicated and the ease of manufacture is inferior to that of a normal multilayer substrate.

  Therefore, the present invention aims to solve the above disadvantages and drawbacks, and to realize an improvement in heat dissipation at a low cost with a relatively simple structure for a substrate on which electronic components are mounted.

  In order to solve the above-described problems, the present invention provides one or a plurality of interlayer heat transfer layers on an inner layer of a multilayer board on which electronic components are mounted, and is generated from the electronic components via the interlayer heat transfer layers. Dissipating heat to the outside is provided.

  In addition, the above-described problem can be solved by providing the interlayer heat transfer layer with a stretched portion that extends part or all of the periphery of the interlayer heat transfer layer from the side surface side of the multilayer substrate, or the interlayer heat transfer layer. The thermal layer is configured as a central layer constituting the multilayer substrate or a layer in the vicinity thereof, or on the plate surface of the multilayer substrate, one or a plurality of layers are provided from the plate surface toward the interlayer heat transfer layer. The interlayer heat transfer layer is made of a conductor, the conductor is copper or a copper-based alloy, or the interlayer The heat transfer layer is more effectively achieved by having a structure that is not connected to a copper layer that forms a circuit pattern for mounting the electronic component on the multilayer substrate.

  Moreover, in order to solve the said subject, this invention is a heat radiating case which accommodates one of the said heat radiating substrates, Comprising: The said heat radiating case is the said heat radiating case which heats from the said board | substrate through the said extending | stretching part. Provided is a heat radiating case that radiates heat to the outside.

  Further, the solution to the above problem is that the heat radiating case includes a housing portion and a lid portion, and has a structure in which an extending portion of the heat radiating substrate is sandwiched between the housing portion and the lid portion. From the case, a heat transfer protrusion is provided so as to be in contact with the interlayer heat transfer layer in the opening of the substrate, and by radiating the heat from the substrate to the outside of the heat dissipation case through the heat transfer protrusion, It is achieved more effectively.

  Further, by using the heat dissipation board or the heat dissipation case using the heat dissipation substrate in an electric power steering device, the heat dissipation of the control device used in the power steering device can be improved at a lower cost, and the usability can be further improved. It is possible.

  In the present invention having the above-described configuration, an interlayer heat transfer layer for heat transfer is provided inside the substrate. Then, the interlayer heat transfer layer is formed of a conductor such as copper, and depending on the amount of heat generated by the electronic component mounted on the substrate, the entire region inside the substrate or a necessary region, It is formed as a plate-like layer. Therefore, by adopting such a structure, it is possible to uniformly conduct and diffuse heat generated from the electronic components mounted on the upper surface and / or lower surface of the substrate into the substrate. Therefore, it is possible to effectively and beforehand prevent thermal deformation and distortion of the substrate due to the heat generation area and the uneven distribution of the heat generation amount in the substrate.

  In the present invention, the interlayer heat transfer layer may be provided with a stretched portion configured such that an outer edge of the interlayer heat transfer layer protrudes from a side surface of the substrate. On the other hand, it is also possible to adopt a configuration in which the opening is formed from the upper surface or the lower surface of the substrate or both of the plate surfaces. For this reason, it is possible to effectively radiate or conduct heat generated from the electronic component from the interlayer heat transfer layer to the outside of the substrate through the extending portion or the opening, and particularly, there is much heat generation. When the interlayer heat transfer layer is provided in the region of the substrate having a portion, the heat is effectively radiated or conducted to the outside of the substrate through the extending portion or the opening of the interlayer heat transfer layer. It is also possible.

  Furthermore, in the present invention, a heat radiating case corresponding to the form of the substrate for housing the heat radiating substrate is provided, and heat from the heat radiating substrate is more efficiently radiated or conducted to the external environment via the heat radiating case. Is possible.

  As described above, according to the heat dissipation board of the present invention and the heat dissipation case used therewith, it is possible to efficiently release heat from the electronic component to the outside of the board. Therefore, for example, when these are used in technical industrial products such as automobiles, and control devices for conductive power steering devices used therefor, the heat dissipation performance of the substrate on which the electronic components used in these are mounted is improved. Even if the control board with relatively low heat generation and the power board with relatively high heat generation, which have been separately configured in the past, are integrated as a single board, problems due to heat generation may occur. It is also possible to prevent. Therefore, according to the present invention, the improvement of the reliability and safety of the technical industrial products in which the electronic components are mounted can be improved with a relatively simple structure and low through improvement of the heat dissipation of the substrate on which the electronic component is mounted. It can be realized at a cost.

It is the figure which showed the basic structure of the electric power steering apparatus provided with the heat sink which concerns on this invention. It is a block diagram which shows the outline of a structure of the control system of the said electric power steering apparatus. BRIEF DESCRIPTION OF THE DRAWINGS It is a sectional side view which shows the outline | summary of the thermal radiation board | substrate which concerns on this invention, (A) is a sectional side view at the time of forming an extending part, (B) is a sectional side view at the time of forming an opening part further. . BRIEF DESCRIPTION OF THE DRAWINGS It is a sectional side view which shows the outline | summary of the thermal radiation board | substrate of this invention, and the thermal radiation case which accommodates this, (A) is a sectional side view at the time of accommodating the thing which formed the extending | stretching part in the thermal radiation board in the thermal radiation case, ( B) is a side sectional view for explaining a heat transfer path when the configuration of (A) is adopted. BRIEF DESCRIPTION OF THE DRAWINGS It is a sectional side view which shows the outline | summary of the thermal radiation board | substrate of this invention, and the thermal radiation case which accommodates this, (A) is what formed the heat-transfer protrusion part in what formed the opening part further in the thermal radiation case, and (A) It is a sectional side view at the time of accommodating in (B), and (B) is a sectional side view explaining the heat-transfer path | route at the time of employ | adopting the structure of (A). It is a perspective view which shows the outline | summary of the thermal radiation board | substrate of this invention, and the thermal radiation case which accommodates this. It is a sectional side view which shows another embodiment of the thermal radiation board | substrate of this invention, and the thermal radiation case which accommodates this.

  Hereinafter, an embodiment of the present invention will be described by taking, as an example, the case where the heat dissipation board of the present invention and the heat dissipation case that accommodates the heat dissipation board are used in an electronic control unit (ECU) that is a control device of an in-vehicle electric power steering apparatus. To do.

  Here, the electric power steering device applies a steering assist force (assist force) to the steering mechanism of the vehicle by the rotational force of the electric motor, and the electric power steering device uses a reduction mechanism to reduce the driving force of the motor. Via a transmission mechanism such as a gear or a belt, the steering shaft or the rack shaft is applied as a steering assist force.

  Such an electric power steering device (EPS) performs feedback control of the motor current in order to accurately generate the torque of the steering assist force.

  Such feedback control adjusts the electric motor applied voltage so that the difference between the steering assist command value (current command value) and the electric motor current detection value is small. This is done by adjusting the duty of PWM (pulse width modulation) control.

  The general configuration of the above-described electric power steering apparatus will be described with reference to FIG. 5, via tie rods 6a and 6b, and further connected to steered wheels 8L and 8R via hub units 7a and 7b. Further, the column shaft 2 is provided with a torque sensor 9 for detecting the steering torque of the handle 1 and a steering angle sensor 14 for detecting the steering angle θ, and the motor 200 for assisting the steering force of the handle 1 is provided with the speed reduction mechanism 3. Are connected to the column shaft 2 via a reduction gear (gear ratio n).

  A control unit (ECU) 10, which is a control device for controlling the electric power steering device, is configured with a micro control unit (MCU) as a basic component, and is supplied with electric power from a battery 13 and is also operated with an ignition key 11. Then, an ignition key signal is input.

  The control unit 10 configured as described above calculates the current command value of the assist (steering assist) command based on the steering torque Th detected by the torque sensor 9 and the vehicle speed Vel detected by the vehicle speed sensor 12, The current supplied to the electric motor 200 is controlled by a voltage control command value Vref obtained by compensating the current command value. The steering angle sensor 14 is not essential and may not be provided, and the steering angle can be obtained from a rotational position sensor such as a resolver connected to the electric motor 200.

  The control unit 10 is connected to a CAN (Controller Area Network) 15 that exchanges various types of vehicle information, and the vehicle speed Vel can be received from the CAN 15. The control unit 10 is also connected to a non-CAN 16 that exchanges communications other than the CAN 15, analog / digital signals, radio waves, and the like.

  The control unit 10 is mainly composed of a CPU (including an MPU, MCU, etc.). FIG. 2 shows general functions executed by a program inside the CPU.

  Therefore, the function and operation of the control unit 10 will be described with reference to FIG. 2. The steering torque Th detected by the torque sensor 9 and the vehicle speed Vel detected by the vehicle speed sensor 12 (or from the CAN 15) are expressed as current command values. Input to the arithmetic unit 210. The current command value calculation unit 210 calculates a current command value Iref1, which is a control target value of the current supplied to the motor 200, using an assist map or the like based on the input steering torque Th and vehicle speed Vel. The current command value Iref1 is input to the current limiting unit 230 via the adding unit 220A, the current command value Irefm with the maximum current limited is input to the subtracting unit 220B, and the motor current value Im fed back from the motor 200 side Deviation I (Irefm-Im) is calculated, and the deviation I is input to PI control unit 250 for improving the characteristics of the steering operation. Then, the voltage control command value Vref whose characteristics are improved by the PI control unit 250 is input to the PWM control unit 260, and the motor 200 is further PWM driven via the inverter circuit 270 as a motor driving unit. Here, the current value Im of the motor 200 is detected by the motor current detector 280 and fed back to the subtractor 220B. Further, the inverter circuit 270 uses an FET as a drive element, and is configured by an FET bridge circuit.

  In addition, the compensation signal CM from the compensation signal generation unit 240 is added to the addition unit 220A, and the compensation of the steering system is compensated by the addition of the compensation signal CM, thereby improving the convergence and inertia characteristics. ing. The compensation signal generation unit 240 adds the self-aligning torque (SAT) 243 and the inertia 242 by the addition unit 244, adds the convergence 241 to the addition result by the addition unit 245, and compensates the addition result of the addition unit 245. The signal CM is used.

  Next, a heat radiating board according to the present invention and a heat radiating case for housing the heat radiating board will be described with reference to FIGS. In the above drawings, members having the same or similar structure or function may be given the same or similar numbers, and some of the common members and elements are not shown or described. There are cases. In addition, in order to facilitate understanding of the present invention, the ratio between the size of the electronic component and the substrate, the heat dissipation case, and the like, and the scale of the drawing may be appropriately changed from the actual ones.

  FIG. 3 is a side view showing an outline of the heat dissipation board of the present invention. In FIG. 3, the central part of the board is omitted. As shown in FIG. 3A, the heat dissipation substrate 300 of the present invention basically includes an interlayer heat transfer layer 330 provided as a plate-like layer between the upper surface and the lower surface of the substrate 310 inside the substrate 310. It is a configuration.

  Of the above, the substrate 310 has a circuit pattern formed by a thin copper layer 313 or the like for mounting the electronic component EC on the upper surface or the lower surface thereof, or both the upper and lower surfaces thereof. In addition to the multi-layer substrate 310 as described in (A), a single-layer substrate composed of a single layer may be used. In FIG. 3, the upper side of the drawing corresponds to the upper surface side of the substrate, and the lower side of the drawing corresponds to the lower surface side of the substrate.

  The interlayer heat transfer layer 330 is a plate-shaped formed body as described above for the purpose of heat conduction made of a material having high thermal conductivity (good heat conductor) provided inside the substrate 310. The good thermal conductor may be composed of a high thermal conductive engineering plastic or the like, or a conductor such as copper or an alloy thereof.

  The interlayer heat transfer layer 330 is provided as an inner layer of the substrate 310, and its position is basically an intermediate position with respect to the thickness direction of the substrate (in the case of a multilayer substrate, a central layer). However, the present invention is not necessarily limited to this. For this reason, when the electronic component EC is mounted on the upper surface of the substrate and not mounted on the lower surface, the electronic component is arranged closer to the position on the upper surface side of the substrate than the intermediate position. It is also possible to arrange so that heat generated from the EC can be easily conducted.

  In addition, the interlayer heat transfer layer 330 basically has the same shape as the plate surface when the plate surface of the substrate 310 is viewed from above, and is thus mounted on the substrate 310. It is possible to uniformly diffuse the heat generated from the produced electronic component EC over the entire substrate and to radiate heat using the entire substrate. However, in the present invention, the present invention is not necessarily limited thereto, and a place where the mounting density of the electronic components EC mounted on the substrate 310 is high, or a highly exothermic one such as an FET is mounted among the electronic components EC. The interlayer heat transfer layer 330 may be formed only in a region near the lower portion of the place. Therefore, in the case of such a configuration, it is possible to suppress the formation amount of the interlayer heat transfer layer 330 to a necessary extent, thereby further diffusing heat from the substrate at a lower cost. Is also possible.

  In addition, as described above, the circuit pattern of the thin copper layer 313 or the like may be formed on the substrate 310, and the through hole TH may be further formed. Therefore, when the interlayer heat transfer layer 330 is composed of a conductor, the interlayer heat transfer layer 330 is formed so as not to be connected thereto. That is, it is formed so as not to come into contact with these copper layers 313 and the like, and is configured to ensure insulation between them.

  In the present embodiment, the interlayer heat transfer layer 330 is formed on the side surface of the board surface of the substrate, that is, on the side surface perpendicular to the upper and lower plate surfaces of the substrate 310, from the side surface side to the interlayer heat transfer layer. A part of the periphery of the layer 330 is extended to have an extended part 335 formed so as to protrude from the side surface.

  The extending portion 335 is intended to more easily conduct heat from the interlayer heat transfer layer 330 to the outside. Therefore, it is possible to expand the radiation of heat from the interlayer heat transfer layer 330 through the extending portion 335. Further, when combined with the heat dissipation case of the present invention as will be described later, It is possible to more effectively release the heat.

  In addition, the extending portion 335 is formed so as to protrude from the side surface of the substrate 310 by extending a part of the peripheral edge of the interlayer heat transfer layer 330. It is possible to determine the optimum form in consideration of the heat radiation efficiency. For this reason, the extending portion 335 may be provided over the entire side surface of the substrate 310, or a high heat-generating property of the electronic component EC mounted on the substrate 310, or in the electronic component EC. It is also possible to provide only a part of the region such as a side surface near the place where the device is mounted.

  Further, in the present invention, the heat radiation efficiency from the substrate 310 can be further improved by providing the opening portion 380 with respect to the substrate 310 as shown in the cross section in FIG.

  That is, FIG. 3B shows a heat dissipation board 350 which is another embodiment of the present invention. The heat dissipating substrate 350 has the same basic configuration as the heat dissipating substrate 330, but in the case of the heat dissipating substrate 350, the plate surface of the substrate 310 is directed from the plate surface toward the interlayer heat transfer layer 330. An opening 380 is provided.

  The opening 380 is a circular hole formed from the plate surface of the substrate 310 toward the interlayer heat transfer layer 330. In the present invention, by providing the opening 380 as described above, the interlayer heat transfer is performed. A structure is adopted in which radiation of heat from the layer is promoted and heat is radiated from the substrate 310 from the opening 380 through the interlayer heat transfer layer 330 more efficiently.

  One or a plurality of the openings 380 can be provided with respect to the plate surface of the substrate 310, and the plate surface of the substrate on which the openings 380 are provided is the upper surface or the lower surface of the substrate 310, or the above figure. As exemplified in the heat dissipation substrate 350 described in 3 (B), the heat dissipation substrate 350 may be provided on both the upper and lower plate surfaces of the substrate 310.

  Further, the size of the opening 380 may be larger than the projected area in the direction of the board surface of the board when one electronic component EC is mounted on the board 310, as exemplified in the heat dissipation board 350. The shape is not necessarily circular as exemplified in the heat dissipation substrate 350, and any shape can be selected according to the shape of the gap of the circuit pattern formed on the substrate 310. is there.

  The position where the opening 380 is provided can be determined in consideration of the amount of heat generated by the electronic component EC or the like mounted on the substrate 310. A plurality of openings may be provided. In addition, as will be described later, when used in combination with the heat dissipation case of the present invention configured with a heat transfer protrusion having conformity to the opening, it is possible to further improve the heat dissipation efficiency from the substrate. is there.

  Next, a heat radiating case that houses the heat radiating substrate of the present invention will be described. The heat radiating case of the present invention is configured to functionally combine the heat radiating substrate and the heat radiating case as described above, for example, as illustrated in FIG. 4 and the like, thereby generating heat generated from the electronic component EC mounted on the substrate, Further, the heat is efficiently radiated to the outside of the substrate.

  FIG. 4 is a side cross-sectional view illustrating a case where, among the heat dissipating substrates as described above, the layer heat transfer layer 330 formed with the extending portion 335 is housed in a heat dissipating case.

  The heat dissipating case 400 is a heat dissipating case configured to conform to the form of the extended portion 335 and the like provided on the substrate to accommodate the heat dissipating substrate. In the case of the present embodiment, the heat radiating case 400 is formed of a lid body 430 and a box body 450, and the end portion 435 of the lid body 430 and the end portion 455 of the box body 450 It has a structure adapted to each other so as to have an integral structure by sandwiching the extending portion 335 formed in the interlayer heat transfer layer 330.

  The heat radiating case 400 is made of a metal material having good heat conductivity such as aluminum or die casting, or a resin, etc., in order to accommodate the heat radiating substrate, and has a strength enough to maintain a certain form. In some cases, it may be a vibration-proof and dust-proof function.

  The form of the box 450 and the lid 430 of the heat radiating case 400 is not particularly limited, but basically, the box 450 and the lid 430 are combined and connected to the heat radiating substrate. The input / output (not shown here) connector portion and the like are configured so as to communicate with the inside and outside of the heat radiating case, while having a form that forms one closed surface as a whole. Further, the box body 450 and the lid body 430 can form a closed space except for the connector portion and the like inside by combining their peripheral portions (455, 435). The peripheral portion is provided with a screwing hole for connecting the box 450 and the lid 430, a caulking means, or a connecting means for press-fitting, etc. Since the closed space can be maintained, the heat dissipation substrate can be stored in the closed space.

  In the case of the heat radiating case 400 shown in FIG. 4, the peripheral portion 455 of the box body 450 and the peripheral portion 435 of the lid body 430 both extend the extending portion 335 formed on the heat radiating substrate from above and below. It is formed so that it can be fixed by being sandwiched. In the present invention, the heat dissipation case 400 and the heat dissipation substrate are integrated with each other, and the heat from the heat dissipation substrate is conducted to the heat dissipation case 400, thereby functionally configured to dissipate heat to the external environment. Has been. And there is no particular limitation on the fixing means by sandwiching as described above. For example, the extending portion 335 may be the peripheral portion 455 of the box body 450 or the peripheral portion 435 of the lid body 430, or both of them. You may press-fit to a peripheral part (455,435). Alternatively, after the extending portion 335 of the heat radiating substrate is fixed to the box 450 of the heat radiating case 400, the cover 430 may be fixed by a fixing means provided separately so as to come into surface contact with the extending portion 335. In addition, the box body 450, the extending portion 335 of the heat dissipation substrate, and the lid body 430 may be simultaneously fixed together by a common screw or the like.

  In addition, the fixing of the heat dissipation board to the heat dissipation case 400 may be performed through a fixing hole formed in the extending portion 335 of the interlayer heat transfer layer 330 of the heat dissipation board. The fixing of the substrate and the formation of the heat conduction path from the substrate to the heat radiating case 400 can be performed simultaneously. However, the fixing of the heat dissipation board to the heat dissipation case 400 is not limited to the above-described means. Therefore, according to the form and location where the extending portion 335 is formed, a fixing means or the like that engages the heat radiating case 400 is provided on the heat radiating substrate separately from the extending portion 335, and the heat radiating substrate and the heat radiating case 400 are separately provided. Can also be fixed.

  When the heat radiating board is housed in the heat radiating case 400 configured as described above, as shown in FIG. 4B, the heat from the heat radiating board can be more efficiently released to the outside. It is.

  That is, FIG. 4B illustrates a heat conduction path when the heat dissipation board as illustrated in FIG. 4A is housed in the heat dissipation case 400. Here, the bold arrow shown with the chain line in the figure has shown the heat-transfer path | route.

  As shown in FIG. 4B, the heat generated from the electronic component EC on the substrate is conducted to the interlayer heat transfer layer 330 according to the present invention through the substrate 310 and the through hole TH. The heat conducted to the interlayer heat transfer layer 330 is further conducted to the extending portion 335 of the interlayer heat transfer layer 330, and the conducted heat is radiated from the extending portion 335 to be a heat dissipation case. The heat is radiated into the interior 400 or radiated from the extending portion 335 to the external environment through the box 450 of the heat radiating case 400 and the peripheral portion (455, 435) of the lid 430. At this time, a heat sink or the like may be separately connected to the heat radiating case 400 to improve the heat radiating efficiency.

  In addition, when the opening 380 is further formed in the heat dissipation substrate, a heat transfer protrusion is formed on the heat dissipation case so as to contact the opening 380, thereby further improving the heat dissipation efficiency. Is possible.

  FIG. 5 (A) shows a case where an opening 380 is further formed in the heat dissipation substrate, and a heat transfer protrusion 580 corresponding to the opening is formed in the heat dissipation case 500 for storing the opening 380. 7 is a side cross-sectional view when the opening 380 and the heat transfer protrusion 580 are thermally connected so as to be able to conduct heat and housed in the heat dissipation case 500. FIG.

  The basic configuration of the heat dissipation case 500 is the same as that of the heat dissipation case 400 described above, but a heat transfer protrusion 580 is provided inside the heat dissipation case 500 at a position corresponding to the opening 380 formed in the heat dissipation substrate. Is different.

  The heat transfer protrusion 580 forms a protrusion inside the heat radiating case 500 with respect to the opening 380 provided in the heat dissipation substrate, and forms a front end of the protrusion in a flat shape. The portion is configured to come into contact with the interlayer heat transfer layer 330 formed to be exposed in the opening 380 by surface contact. In the present invention, by forming the heat transfer protrusion 580 in this way, heat from the interlayer heat transfer layer 330 exposed in the opening 380 formed in the substrate 310 is transferred to the heat transfer protrusion 580. Heat is transferred directly and conducted to the heat radiating case 500 through this, so that heat can be efficiently radiated from the heat radiating case 500 to the outside.

  Therefore, the heat transfer protrusion 580 is formed on the inside of the lid 530 and / or the box 550 of the heat radiating case 500, or on both sides of the board plate of the opening 380 of the heat radiating board housed in the heat radiating case 500. It is formed in accordance with the position on the surface and the distance from the inside of the lid 530 or the box 550 to the interlayer heat transfer layer 330 in the opening 380 of the heat dissipation substrate.

  The material of the heat transfer protrusion 580 may be basically the same as the material of the heat dissipation case 500, but is different in consideration of the ease of manufacturing the heat dissipation case 500 and the heat transfer protrusion 580. It may be formed of materials, or may be the same material but not formed at the same time and formed separately and combined later.

  In addition, the heat transfer protrusion 580 is basically used for heat conduction from the heat dissipation substrate to the heat dissipation case 500, but is exposed between the tip of the heat transfer protrusion 580 and the opening 380. A screw hole or the like may be formed in a part of the heat transfer layer 330 to be used for connection between the substrate 310 and the heat radiating case 500. That is, an opening 380 is provided at a corresponding position on the upper surface and the lower surface of the substrate 310, the heat transfer protrusion 580 is formed from the box body 550 of the heat radiating case in the opening 380 on the lower surface side, and the opening 380 on the upper surface side. In this case, the heat transfer protrusion may not be provided from the lid 530 to the above position, and a screw or the like may be inserted instead to fix the heat dissipation board to the box 550.

  FIG. 5B illustrates the flow of heat conduction between the heat dissipation case 500 and the heat dissipation board shown in FIG. 5A formed as described above. Here, the bold arrows indicated by chain lines in the figure indicate the heat transfer paths as in the case of FIG. 4B.

  As shown in FIG. 5B, heat generated from the electronic component EC on the substrate is conducted to the interlayer heat transfer layer 330 according to the present invention through the substrate 310 and the through hole TH, and the interlayer heat transfer is performed. The heat is radiated from the extending portion 335 of the layer 330 to the inside of the heat radiating case 500 or is radiated to the outside through the box 550 of the heat radiating case 500 and the peripheral portion (555, 535) of the lid 530. In addition, in the case of the present embodiment, in addition to this, with respect to the interlayer heat transfer layer 330 exposed inside the opening 380 formed in the heat dissipation substrate, the heat transfer protrusions from the inside of the heat dissipation case 500. Since 580 is formed, heat is radiated from the interlayer heat transfer layer 330 through the heat transfer protrusion 580. Therefore, heat dissipation from the heat dissipation substrate can be more effectively performed by the heat transfer protrusion 580 provided in the heat dissipation case 500.

  FIG. 6 is a perspective view showing still another configuration example of the heat dissipation board and the heat dissipation case configured as described above.

  In the example described in FIG. 6, the heat dissipation substrate 600 is configured based on a substantially quadrilateral substrate 310, and extended portions 335 extended from the interlayer heat transfer layer 330 are formed at the four corner positions of the substrate 310. The extending portion 335 is provided with a hole for fixing the substrate 600 between the lid body 650 </ b> A and the box body 650 </ b> B constituting the heat radiating case 650 with screws 654. In the substrate 600, the electronic component EC mounted on the substrate 310 and the circuit pattern formed on the substrate are omitted.

  In addition, the heat dissipation substrate 600 has a connector 603 formed on a part of the periphery of the substrate so that an electronic circuit formed on the substrate 310 can be electrically coupled to an external electric device or the like. In addition, four circular openings 380 are provided on the upper side of the substrate 310, and one circular opening 380 (not shown) is provided on the lower side. The interlayer heat transfer layer 330 is exposed.

  Further, the heat radiating case 650 has a box shape capable of accommodating the heat radiating substrate 600 inside, and the cover body 650A constituting the heat radiating board 600 is arranged near the periphery thereof. A hole through which a screw 654 for fixing together with the box 650B is passed from above the heat dissipation substrate 600 is formed. Further, four heat transfer protrusions 580 are formed on the inner side of the lid 650A, as shown in FIG. 6 with a part of the internal structure shown by a chain line, and the four heat transfer protrusions 580 are formed. The front end of each of the layers is formed in a planar shape so that it can come into surface contact with the interlayer heat transfer layer 330 exposed inside the four openings 380 provided in the heat dissipation substrate 600.

  The box body 650B of the heat radiating case 650 constitutes a lower portion of the heat radiating case 650, and the box 650B is placed under the heat radiating substrate 600 at the inner side of the peripheral portion of the heat radiating case 650. A heat transfer locking portion 656 having a hole through which a screw 654 for integration and fixing together with the lid body 650A is formed from the side is formed. The heat transfer locking portion 656 has a purpose of locking the heat radiating substrate 600 to the heat radiating case 650 and also conducting heat from the extending portion 335 formed on the heat radiating substrate 600 to the heat radiating case 650. Therefore, it is formed in a similar shape having a size equivalent to that of the extending portion 335.

  Further, one heat transfer protrusion 580 is provided on the box 650B of the heat radiating case 650 from the inner surface of the bottom surface of the box 650B, and the heat transfer protrusion 580 is connected to the heat radiating substrate 600. The interlayer heat transfer layer 330 exposed to the inside of one (not shown) opening 380 provided on the bottom surface side can be contacted. An external support 605 for attaching the heat dissipation case 650 to an external device is also provided on the outer surface of the box 650B.

  The heat dissipation board 600 and the heat dissipation case 650 configured as described above are integrally connected via the screws 654 as described above, and the heat from the heat dissipation board 600 is the heat dissipation. It is transmitted to the heat radiating case 650 through the entire plate surface of the substrate 600, the extending portion 335, and the opening 380, and is thereby discharged from the heat radiating case 650 to the external environment.

  Therefore, according to the present invention, the heat generated from the electronic components mounted on the substrate can be released at a low cost with a relatively simple structure by the heat dissipation substrate and the heat dissipation case storing the heat dissipation substrate. .

  The above-described embodiment of the present invention shows a configuration example of the present invention, and the present invention is not limited to the above, and various forms are adopted within the scope of the gist of the present invention. Is also possible. Therefore, for example, as shown in a side sectional view in FIG. 7, a plurality of interlayer heat transfer layers 330 can be provided in the heat dissipation substrate of the present invention.

  In the example shown in FIG. 7, the interlayer heat transfer layer constituting the heat dissipation substrate of the present invention is provided as two separated layers (330A, 330B). In this case, the two interlayer heat transfer layers (330A, 330B) are arranged apart from each other in a region near the center in the thickness direction in the substrate 310, and are mounted on the upper and lower surfaces of the substrate. It is possible to arrange the electronic parts EC closer to each other and to increase the cross-sectional area for heat transfer. Therefore, more effective heat transfer is possible by adopting such a configuration.

  Further, as shown in FIG. 7B, the opening 380 can be formed from the plate surface of the substrate 310 with respect to the interlayer heat transfer layer (330A, 330B) constituted by the two layers.

  In that case, the opening 380 with respect to the interlayer heat transfer layer (330A, 330B) constituted by two layers as described above is formed from the plate surface of the substrate 310 immediately adjacent to the interlayer heat transfer layer. Formed against. Therefore, in the configuration example shown in FIG. 7B, the lower interlayer heat transfer layer 330B from the lower surface of the substrate 310 is changed to the lower interlayer heat transfer layer 330B from the lower surface of the substrate 310. An opening 380 is formed for the upper interlayer heat transfer layer 330A of the substrate 310, and an opening 380 is formed from the upper surface of the substrate 310 to the upper interlayer heat transfer layer 330A. .

  Therefore, the heat radiating case 700 that houses the heat radiating substrate in which the opening 380 is formed as described above has the above-described opening by the heat transfer protrusion 780 formed inside the lid 730 with respect to the upper opening 380. Heat from the interlayer heat transfer layer 330A exposed in the portion 380 is conducted, and the lower opening 380 is introduced into the opening 380 by a heat transfer protrusion 780 formed inside the box 750. Heat from the exposed interlayer heat transfer layer 330B is conducted to the external environment through the heat dissipation case 700. Therefore, in the present invention, even with the above-described configuration, the heat generated from the electronic component EC can be effectively released to the external environment by the heat dissipation board and the heat dissipation case, and the problem due to heat generation of the board can be solved. It is.

1 Handle 2 Column shaft (steering shaft, handle shaft)
3 Deceleration Mechanism 4a 4b Universal Joint 5 Pinion Rack Mechanism 6a 6b Tie Rod 7a 7b Hub Unit 8L 8R Steering Wheel 9 Torque Sensor 10 Control Unit 11 Ignition Key 12 Vehicle Speed Sensor 13 Battery 14 Steering Angle Sensor 15 CAN
16 Non-CAN
210 Current command value calculation unit 230 Current control unit 240 Compensation signal generation unit 250 PI control unit 260 PWM control unit 270 Inverter circuit 280 Motor current detector 300 350 Heat dissipation substrate 310 Substrate 313 Copper layer 330 Interlayer heat transfer layer 335 Extension unit 380 Opening Part 400 500 heat dissipation case 430 530 650A cover body 435 535 cover body peripheral part 450 550 650B box body 455 555 box body peripheral part 580 780 heat transfer protrusion 603 connector 605 external support 654 screw 656 heat transfer locking part EC electronic component TH Through hole

Claims (12)

  One or a plurality of interlayer heat transfer layers are provided on an inner layer of a multilayer substrate on which electronic components are mounted, and heat generated from the electronic components is released to the outside through the interlayer heat transfer layers. Heat dissipation board.   2. The heat dissipation substrate according to claim 1, wherein the interlayer heat transfer layer includes an extending portion that extends a part or all of a periphery of the interlayer heat transfer layer from a side surface side of the multilayer substrate.   The heat dissipation substrate according to claim 1, wherein the interlayer heat transfer layer is configured as a central layer constituting the multilayer substrate or a layer in the vicinity thereof.   The heat dissipation substrate according to any one of claims 1 to 3, wherein one or a plurality of openings are provided on the plate surface of the multilayer substrate from the plate surface toward the interlayer heat transfer layer.   The heat dissipation substrate according to claim 1, wherein the interlayer heat transfer layer is made of a conductor.   The heat dissipation board according to claim 5, wherein the conductor is copper or an alloy containing copper as a main component.   The heat dissipation board according to claim 5 or 6, wherein the interlayer heat transfer layer has a structure not connected to a copper layer constituting a circuit pattern for mounting the electronic component on the multilayer board.   A heat dissipation case for housing the heat dissipation substrate according to any one of claims 2 to 7, wherein the heat dissipation case dissipates heat from the substrate to the outside of the heat dissipation case via the extending portion. Features a heat dissipation case.   The heat dissipation case according to claim 8, wherein the heat dissipation case includes an accommodation portion and a lid portion, and has a structure in which an extending portion of the heat dissipation substrate is sandwiched between the accommodation portion and the lid portion.   A heat dissipation case for housing the heat dissipation substrate according to any one of claims 4 to 7, wherein a heat transfer protrusion is provided from the heat dissipation case so as to be in contact with an interlayer heat transfer layer in an opening of the substrate. A heat radiating case, wherein heat from the substrate is radiated to the outside of the heat radiating case through the heat transfer protrusion.   An electric power steering apparatus using the heat dissipation board according to claim 1. An electric power steering device using a heat radiating case that houses the heat radiating board according to claim 8.