JP5360419B2 - Electronic circuit board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic circuit board that dissipates heat generated by shunt resistance to the outside with high efficiency without increasing the number of components. <P>SOLUTION: The electronic circuit board includes a substrate 3 and a resistor 1 connected on one principal surface of the substrate 3. A slit 6 is formed on one principal surface of the substrate 3 which is opposed to the resistor 1. The electronic circuit board further includes another resistor 1 which is disposed on the substrate 3 on another principal surface being opposite to the one principal surface so as to face each other, and the resistor 1 connected on the one principal surface of the substrate 3 and the resistor 1 connected on the other principal surface of the substrate 3 can be arranged at a position shifted from each other in a direction along the principal surfaces of the substrate 3. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an electronic circuit board, and more particularly to an electronic circuit board on which a shunt resistor is surface-mounted.

  In an inverter device or the like, for example, an electronic circuit board including a current detection circuit incorporating a DCCT (DC Current Transformer) or a shunt resistor is used to detect a current flowing through a motor. The inverter device is said to have a large energy saving effect. For this reason, in recent years, the field of use of inverter devices has expanded especially as a measure against global warming.

  If, for example, a shunt resistor is used as the current detection circuit of the inverter device, the shunt resistor generates heat when a current flows through the shunt resistor. The greater the current flowing through the shunt resistor, the greater the amount of heat generated.

  In the case of a surface mount type (flat plate shape) shunt resistor, if it is placed on the main surface of the substrate that constitutes the electronic circuit board, the shunt resistor generates heat so that it opposes the substrate and the shunt resistor. Propagates toward the (connected) member. For this reason, the temperature of the said board | substrate and member rises. Then, there is a possibility that the substrate and the member are heated to a temperature exceeding the upper limit value of these allowable temperatures.

  If the temperature of the substrate rises in this way, there is a possibility that problems such as damage to the substrate and malfunction of the electronic circuit substrate may occur. Here, the main surface refers to the main surface having the largest area among the surfaces.

  In order to suppress the temperature rise of such a board | substrate and a member, it is possible to radiate | eradiate outside smoothly, for example from a shunt resistance, without transmitting heat to a board | substrate. Therefore, for example, in Japanese Patent Application Laid-Open No. 2009-10082 (Patent Document 1), in an electronic circuit device in which a flat shunt resistor is mounted on a substrate, a radiator is provided on the opposite side of the shunt resistor from the substrate. . That is, in the electronic circuit device, the heat generated by the shunt resistor is dissipated from the radiator instead of propagating toward the substrate. Therefore, in the electronic circuit device, heat generated by the shunt resistor is transmitted to the substrate and the temperature of the substrate is prevented from rising.

JP 2009-10082 A

  However, in the electronic circuit device disclosed in Japanese Patent Application Laid-Open No. 2009-10082, the number of components constituting the electronic circuit device increases as the heat sink is installed for the shunt resistor. As the number of parts increases, the cost of the device increases, the size of the device itself increases, and problems such as reduced utility can arise.

  The object of the present invention has been made in view of the above problems. The object is to provide an electronic circuit board that can dissipate the heat generated by the shunt resistor to the outside with high efficiency without increasing the number of components.

An electronic circuit board according to the present invention is an electronic circuit board including a substrate and a resistance member connected on one main surface of the substrate. A slit is formed on the main surface of the substrate facing the resistance member. A plurality of the slits are formed at positions facing the resistance member, and further include another resistance member arranged so as to face the other main surface opposite to the one main surface on the substrate. The resistance member and the other resistance member are arranged at positions shifted from each other in the direction along the main surface of the substrate. The resistance member and the other resistance member are connected in parallel on the electronic circuit board. The slit extends in a direction along the long side of the electronic circuit board.

  In the resistance member (shunt resistance), the heat of the shunt resistance is also dissipated by causing convection of a gas such as air in a region facing the main surface of the substrate. That is, the heat generated by the shunt resistance is dissipated by contacting the surface of the shunt resistance while causing gas convection in a slit (a region where no member is present) formed on the main surface of the substrate. That is, by forming slits on the main surface of the substrate, a region where heat of the shunt resistor is dissipated by convection is increased. For this reason, the substrate and the shunt resistor are cooled with high efficiency.

It is a perspective view which shows the aspect of the external appearance of the electronic circuit board which concerns on the reference form 1 of this invention. It is a top view of the electronic circuit board of FIG. It is a schematic sectional drawing in the part which follows the III (IV) -III (IV) line | wire of FIG. It is a schematic sectional drawing of the modification of FIG. It is a perspective view which shows the aspect of the external appearance of the electronic circuit board which concerns on the reference form 2 of this invention. FIG. 6 is a top view of the upper main surface of the electronic circuit board of FIG. 5. It is a top view of the lower main surface of the electronic circuit board of FIG. It is a schematic sectional drawing in the part which follows the VIII (IX) -VIII (IX) line | wire of FIG. It is a schematic sectional drawing of the modification of FIG. It is a schematic sectional drawing which shows the other structural example in the part which follows the XX line of FIG. It is a perspective view which shows the aspect of the external appearance of the electronic circuit board which concerns on Embodiment 1 of this invention. It is a top view of the upper main surface of the electronic circuit board of FIG. It is a schematic sectional drawing in the part which follows the XIII-XIII line | wire of FIG. It is a perspective view which shows the aspect of the external appearance of the electronic circuit board as a modification of Embodiment 1 of this invention.

Hereinafter, with reference to the drawings, a description will be given implementation of the present invention. Incidentally, in the implementation, the elements that perform the same function are denoted by the same reference numerals, and description thereof will not be repeated unless particularly necessary.

( Reference form 1)
Referring to FIGS. 1 to 3, an electronic circuit board according to this reference embodiment includes a resistor 1, a substrate 3. Resistor 1 (resistive member) is a member used as a shunt resistor for detecting a current value used in, for example, an inverter device.

  In order to pass a current through the resistor 1, the resistor 1 is preferably made of a conductor having electrical resistance, and specifically, for example, is preferably made of metal, metal glaze, or carbon. The substrate 3 is a substrate that serves as a base for the entire electronic circuit board.

  Since the resistor 1 is surface-mounted on the substrate 3, it has, for example, a flat plate shape. Resistor 1 is connected to, for example, solder 4 on land 2 arranged in a partial region on one main surface of substrate 3 (on the upper main surface in FIGS. 1 and 3). The land 2 is a conductive flat plate member made of a conductor such as copper.

  Resistor 1 arranged so as to straddle two lands 2 having a long shape in the direction along the main surface of substrate 3 is connected to substrate 3. The resistor 1 and the land 2 on the substrate 3 are connected by solder 4.

  On the main surface on the upper side of the substrate 3, conductor thin films 5 such as copper are disposed at two locations. All of these conductor thin films 5 are formed on the main surface of the substrate 3 below the lands 2. In other words, the land 2 is arranged in a partial region on the main surface of the conductor thin film 5 formed on the main surface of the substrate 3. However, the conductor thin film 5 is not shown in FIG.

  The land 2 is a region made of, for example, copper or the like like the conductor thin film 5, and a partial region of the conductor thin film 5 is defined as the land 2. A solder resist material is applied on the surface of the conductive thin film 5, but no solder resist material is applied on the surface of the land 2. For this reason, the resistor 1 and the substrate 3 are connected to the surface of the land 2 by the solder 4.

  Of these, the upper conductor thin film 5 shown in FIGS. 1 and 2 is electrically connected to the rectangular (upper) long side formed by the main surface of the substrate 3. The lower conductor thin film 5 shown in FIGS. 1 and 2 is electrically connected to a rectangular (left side) short side formed by the main surface of the substrate 3.

  Of the region facing the lower main surface of the resistor 1, a slit 6 is formed particularly in the region facing the vicinity of the center of the main surface of the resistor 1. The slit 6 is formed on the main surface of the substrate 3 and is a through-hole (groove) -like region formed so as to penetrate between a pair of opposing main surfaces of the substrate 3. 1 and 2, the slit 6 has a rectangular shape with respect to the direction along the main surface of the substrate 3. For example, the slit 6 may have an elliptical shape, and the planar shape of the slit 6 may be an arbitrary shape. it can. Therefore, the resistor 1 is disposed so as to straddle the two lands 2 while covering the center portion of the slit 6 from above.

  That is, since the slit 6 is formed in the substrate 3, the substrate 3 is not disposed in a region where the central surface of the lower surface of the resistor 1 is particularly opposed to the center, and the resistor 1 is opposed to the gap. It has become.

Next, the operation principle of the electronic circuit board of the present reference embodiment.

  A current is passed through the resistor 1 by applying a voltage between the rectangular (upper) long side and the (left) short side formed by the main surface of the substrate 3. The current value flowing through the resistor 1 is measured from the voltage value at this time and the resistance value of the resistor 1. Here, a circuit such as an inverter device using an electronic circuit board is assembled so that the current value flowing through the resistor 1 is the same as the current value flowing through an external load such as a motor connected to the board 3. For example, the value of the current flowing through the external load can be detected.

Next, the function and effect will be described in this reference form.

  When a current is passed through the resistor 1, the resistor 1 generates heat. At this time, air convection occurs in the region on the upper main surface of the resistor 1 in FIGS. The heat generated by the resistor 1 travels outside the resistor 1 along the air convection. That is, the resistor 1 is air-cooled by air convection. In this way, the heat generated by the resistor 1 is dissipated. Part of the heat generated by the resistor 1 moves toward the substrate 3 via the land 2 to which the resistor 1 is connected.

  In addition to the heat radiation of the resistor 1 through the path described above, in the case of the electronic circuit board of FIGS. 1 to 3, the heat is also radiated in the slit 6 provided in the region facing the lower main surface of the resistor 1. The The slit 6 is an area where the substrate 3 is partially removed, such as a through hole. In other words, air convection occurs in the slit 6 which is a part of the region facing the lower main surface of the resistor 1. For this reason, the heat generated by the resistor 1 travels outside the resistor 1 along the convection of the air. The heat of the substrate 3 is also radiated by the air convection in the slit 6. This is because the slit 6 is an area where the substrate 3 is partially removed, and the space of the slit 6 is in contact with the substrate 3.

As described above, the electronic circuit board of the present reference embodiment, the heat resistor 1 is not on the main surface of the upper resistor 1 only, is radiated from the resistor 1 of the lower main surface on. That is, since the slit 6 is formed on the main surface of the substrate 3, the area of the surface of the resistor 1 that can radiate heat to the outside of the electronic circuit board by using air convection is increased. . In other words, the efficiency with which the heat of the resistor 1 is dissipated to a place other than the electronic circuit board such as the board 3 and the components of the inverter device is increased. For this reason, the temperature rise of the board | substrate 3 or the resistor 1 can be suppressed highly efficiently.

Moreover, the electronic circuit board of this reference form improves the efficiency of heat dissipation of the resistor 1 and the board 3 by forming slits 6 in the board 3 without installing a radiator or the like, for example. That is, the number of parts constituting the electronic circuit board is not increased. For this reason, the increase in the cost of an electronic circuit board, the fall of the utility accompanying the increase in the number of the components of an electronic circuit board, etc. can be suppressed.

  Alternatively, the electronic circuit board may be configured to include the conductive thin film 5 and the land 2 on both the upper main surface and the lower main surface of the substrate 3 as shown in the schematic cross-sectional view of FIG. Good. In this case, for example, the upper conductor thin film 5, the substrate 3, and the lower conductor thin film 5 are passed through in the vertical direction in FIG. 4 to electrically connect the upper conductor thin film 5 and the lower conductor thin film 5. A through hole 7 may be formed. In this case, although not shown in FIG. 4, the resistor 1 is connected to the region facing the lower main surface of the substrate 3 by the solder 4 in the same manner as the region facing the upper main surface of the substrate 3. May be.

( Reference form 2)
This reference form is different from the reference form 1 in the configuration and arrangement of the resistors. The following describes the structure of the present reference embodiment.

Referring to FIGS. 5 to 7, the electronic circuit board of the present reference embodiment, the resistor 1 is provided with a plurality of (five). The size of each resistor 1 is smaller than the resistor 1 of the reference form 1. These resistors 1 are arranged in parallel along the extending direction of the long side of the substrate 3.

  However, these resistors 1 are not only on one main surface (the upper main surface in FIG. 5) of the substrate 3, but also on the other main surface (the lower surface in FIG. 5) opposite to the one main surface of the substrate 3. It is also arranged in a region facing the main surface on the side. A part of these five resistors 1 (resistive members) and the other resistors 1 (other resistor members) other than the part of the resistors 1 are along the main surface of the substrate 3. It arrange | positions in the position which mutually shifted | deviated regarding the direction (here especially longitudinal direction among the main surfaces of the board | substrate 3).

  Specifically, with respect to the direction along the long side of the main surface of the substrate 3 (left-right direction in FIGS. 5 to 7), one end portion (one short side) of the five resistors 1 arranged in parallel. The first, third, and fifth resistors 1 counted from the side) are arranged in a region of the substrate 3 that faces the lower main surface of FIG. On the other hand, the 2nd and 4th resistor 1 counted from one edge part is arrange | positioned in the area | region facing the upper main surface of FIG. On the other hand, for example, the first, third, and fifth resistors 1 counted from one end are disposed in the region facing the main surface on the upper side of the substrate 3. May be disposed in a region facing the lower main surface of the substrate 3.

5 to 7, one end of the second and fourth resistors 1 counted from (one short side) of the substrate 3, as shown in the sectional view of FIG. 8, reference embodiment 1 Similar to the resistor 1, it is connected by solder 4 so as to be connected to the land 2 on the upper main surface of the substrate 3. 8 shows the same mode as FIG. 3 and FIG. 9 shows the same mode as that of FIG. 4, but it may have any mode.

  Further, as shown in FIG. 10, the structure of the cross section along line XX in FIG. 6 can also be a structure in which the top and bottom of FIG. 9 are turned upside down, similarly to the structure shown in FIG. Alternatively, the cross-sectional structure along line XX in FIG. 6 may be a structure in which the top and bottom in FIG. 8 are reversed.

  Specifically, the first, third and fifth resistors 1 counted from one end (one short side) of the substrate 3 shown in FIG. 6 are connected to the substrate 3 in the manner described below. May be. As shown in the cross-sectional view of FIG. 10, the through hole 7 penetrates the thickness direction (vertical direction in FIG. 10) of the substrate 3 from the upper main surface of the substrate 3 to the lower main surface of the substrate 3. Is arranged.

  The through hole 7 is formed so as to penetrate the conductor thin film 5 and the substrate 3 on the upper main surface of the substrate 3 and the conductor thin film 5 on the lower main surface of the substrate 3 in the vertical direction of FIG. Yes. Since the metal material is plated inside the through hole 7, the conductive thin film 5 on the upper main surface of the substrate 3 is electrically connected to the conductive thin film 5 on the lower main surface of the substrate 3. The

  Here, the land 2 arranged in a partial region on the main surface of the conductor thin film 5 on the lower side of the substrate 3 and the resistor 1 are connected by the solder 4. Then, the resistor 1 is electrically connected to the conductive thin film 5 on the upper main surface of the substrate 3 and the like.

By connecting as described above, the resistor 1 arranged so as to face the lower main surface of the substrate 3 is also electrically connected to the conductive thin film 5 on the upper side of the substrate 3. Therefore, for the electronic circuit board of the present reference embodiment, with respect to all of the resistors 1, operated by the same operation principle as the resistor 1 of the electronic circuit board of Reference Embodiment 1.

Next, the function and effect will be described in this reference form. Electronic circuit board according to this reference embodiment, in addition to the same advantages as those in the electronic circuit board of Reference Embodiment 1, has the operational effects described below.

A plurality of resistors 1 of the electronic circuit board of the present reference embodiment, respectively are connected in parallel in an electric circuit. For this reason, the value of current flowing through one resistor 1 can be made smaller than the value of current flowing through the resistor of Reference Embodiment 1. For this reason, the calorific value of each resistor 1 can be made smaller than the resistor 1 of the electronic circuit board of the reference form 1.

In the electronic circuit board of the present reference embodiment, the resistor 1 to be more parallel to reduce the size, instead of placing all on one main surface of the substrate 3, one main surface side of the substrate 3 And the other main surface side are alternately arranged in the direction along the long side of the substrate 3. For this reason, for example, compared with the case where five resistors 1 are arranged in parallel only on one main surface side of the substrate 3, the efficiency with which the heat of the resistor 1 is moved (heat radiation) is increased.

  Although five resistors 1 are arranged on the entire electronic circuit board, only two (three) resistors 1 are arranged on one main surface side (the other main surface side) of the substrate 3. For this reason, for example, as compared with the case where five resistors 1 are arranged in parallel only on one main surface side of the substrate 3, air convection on the main surface of each resistor 1 on the side not facing the substrate 3 (slit 6). Increases the efficiency of heat dissipation. This is because the amount of air convection for air-cooling one main surface of the resistor 1 can be increased.

Therefore, a plurality of resistors 1 as in this reference embodiment are arranged separately in the front and back surfaces of the substrate 3, and the mutually offset positions (upper and lower major surfaces of the substrate 3 with respect to the main surface of the substrate 3 By arranging in the (opposite region), the efficiency of radiating the heat generated by the resistor 1 is increased. Therefore, the temperature rise of the resistor 1 and the board | substrate 3 can be suppressed further reliably.

The reference form 2 of the present invention is different from the reference form 1 of the present invention only in each of the points described above. In other words, the configuration, conditions, procedures, effects, and the like that are not described above in Reference Embodiment 2 of the present invention are all in accordance with Reference Embodiment 1 of the present invention.

(Embodiment 1 )
This embodiment differs from the reference embodiments 1 and 2 in the configuration of the slits. Hereinafter, the configuration of the present embodiment will be described.

With reference to FIGS. 11-13, the electronic circuit board of this Embodiment has two slits 6 formed therein. Specifically, only one slit 6 extending in the direction along the long side of the substrate 3 is formed in the reference embodiments 1 and 2, whereas two slits are formed in the present embodiment. 6 are juxtaposed in the direction along the short side of the substrate 3.

These two slits 6 are preferably formed at a certain interval in the central portion in the short side direction of the substrate 3 sandwiched between two lands 2 on which one resistor 1 is placed. 11 to 13, the two slits 6 of the present embodiment are formed in the electronic circuit board having the plurality of resistors 1 of the reference embodiment 2. However, for example, as shown in FIG. 14, the two slits 6 of the present embodiment may be formed on the electronic circuit board of Reference Embodiment 1, that is, the electronic circuit board having the single resistor 1.

  Also, two slits 6 are formed in the electronic circuit boards of FIGS. However, three or more slits 6 may be formed on the main surface of the substrate.

Next, the effect of this Embodiment is demonstrated. The electronic circuit board of the present embodiment has the following operational effects in addition to the operational effects similar to those of the electronic circuit boards of Reference Embodiments 1 and 2.

  If a plurality of slits 6 are formed at regular intervals, for example, as shown in the cross-sectional view of FIG. 13, the resistor 1 in addition to the end portion in the short side direction of the resistor 1 on which the land 2 is arranged. The resistor 1 can be connected to the substrate 3 using the adhesive 8 also in the central portion (region sandwiched between the two slits 6) in the short side direction.

  When the resistor 1 has a flat plate shape that is surface-mounted on the substrate 3, the connection with the resistor 1 in the region sandwiched between the two slits 6 on the main surface of the substrate 3 is performed as described above. This can be done particularly easily. For this reason, compared with the case where the area | region pinched | interposed into the slit 6 does not exist, the fixation by the soldering of the resistor 1 and the board | substrate 3 can be made easy, and the said fixation can be made still more reliable.

Although in FIG. 13 is a cross-sectional view of a case where the through holes 7 in the same manner as FIG. 3 is not formed, in the first embodiment, as in Embodiment 1 and Reference Embodiment 2 of Reference, the through holes 7 The upper surface and the lower surface of the main surface of the substrate 3 may be electrically connected.

The first embodiment of the present invention, the above-mentioned respects only differs from the first embodiment and the second reference in the present invention. In other words, the configurations, conditions, procedures, effects, and the like that have not been described above for Embodiment 1 of the present invention are all in accordance with Reference Embodiments 1 and 2 of the present invention.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention is particularly excellent as a technique for radiating heat from an electronic circuit board at low cost and high efficiency.

  1 resistor, 2 lands, 3 substrate, 4 solder, 5 conductor thin film, 6 slit, 7 through hole, 8 adhesive.

Claims (1)

A substrate,
An electronic circuit board comprising a resistance member connected on one main surface of the board;
A slit is formed on the main surface of the substrate facing the resistance member ,
A plurality of the slits are formed at positions facing the resistance member,
The substrate further comprises another resistance member disposed to face the other main surface opposite to the one main surface in the substrate,
The resistance member and the other resistance member are arranged at positions shifted from each other with respect to a direction along the main surface of the substrate,
The resistance member and the other resistance member are connected in parallel on the electronic circuit board,
The slit is an electronic circuit board extending in a direction along a long side of the electronic circuit board.

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