JP7007131B2 - Heat dissipation structure in circuit board equipment - Google Patents

Description

The present invention has a board, plus and minus power lines printed on one side of the board, and at least six switching elements mounted on one side of the board, while converting power from direct current to three-phase alternating current. The present invention relates to a circuit board device in which an inverter unit is housed and fixed in a metal case that also serves as a heat sink, and particularly to an improvement in its heat dissipation structure.

A circuit board device in which a substrate on which a heat generating element such as a switching element is mounted is housed and fixed in a metal case that also serves as a heat sink is already known in, for example, Patent Document 1.

Japanese Unexamined Patent Publication No. 2013-21348

In the circuit board device disclosed in Patent Document 1, the heat generating element mounted on the substrate is in contact with the case via the insulating heat radiating sheet, and the heat from the heat generating element is radiated to the case side. When such a technique is applied to a circuit board device having an inverter unit, it is possible to effectively dissipate heat from the switching element to the case side by interposing a heat dissipation sheet between the switching element and the case. In the inverter unit, the current flowing in each of the three phases on the output side is averaged and flows in the positive and negative power supply lines, so it is necessary to efficiently dissipate the heat from the positive and negative power supply lines.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a heat dissipation structure in a circuit board device capable of efficiently performing heat dissipation from positive and negative power supply lines to improve performance. do.

In order to achieve the above object, the present invention has a substrate, plus and minus power lines printed on one surface of the substrate, and at least six switching elements mounted on one surface of the substrate. In a circuit board device in which an inverter that converts power from direct current to three-phase alternating current is housed and fixed in a metal case that also serves as a heat sink, the case has a plate-shaped flat portion having two sides extending in parallel in one direction. The substrate comprises a bottom wall having a pair of stepped portions that bend in the same direction from the two sides of the flat portion and then bend in directions that are separated from each other, and the substrate has one surface of the flat portion of the case. The switching element is housed in the case so as to face the inner surface of the substrate, and the switching element is brought into contact with the flat portion via an electrically insulating heat-dissipating sheet, and the one surface of the substrate in a direction intersecting the one direction. The positive and negative power lines, which are printed so as to extend in parallel in one direction, are respectively bonded to the pair of steps via an adhesive having electrical insulation and high thermal conductivity. The step portion from the flat portion is more than the distance from the pattern surface of the positive and negative power supply lines to the protruding end surface of the switching element in a state where the heat radiation sheet is removed from the one surface of the substrate. The first feature is that the height is set small .

The first substrate 14 of the embodiment corresponds to the substrate of the present invention.

The second feature of the present invention is that, in addition to the configuration of the first feature, the step portion is bent at a right angle from the two sides of the flat portion and rises, and the substrate is supported by the step portion . And.

The third feature of the present invention is that, in addition to the configuration of the first or second feature, a space is formed between the switching elements .

Further, in addition to the configuration of the first to third features, the present invention is attached to the substrate at both ends of the substrate in a direction intersecting the one direction on the surface opposite to the one surface. A fourth feature is that a connector to be connected is arranged, and the connector does not protrude from the one surface of the substrate.

Further, in the fifth aspect of the present invention, in addition to the configuration of the fourth feature, a second substrate connected to the connector is arranged on the upper surface of the substrate so as to be supported by the connector. It is a feature of.

According to the first feature of the present invention, in the inverter unit, the plus and minus power supply lines are brought into contact with the case via an adhesive which is a heat dissipation member having electrical insulation and thermal conductivity. It is possible to efficiently dissipate and cool the heat from the positive and negative power supply lines that flow by averaging the current flowing in each of the three phases on the output side, and it is possible to improve the output performance and the same output. It is possible to reduce the size and weight of the circuit board device as compared with the one.

Further, when the switching element comes into contact with the case via the heat radiating sheet having electrical insulation, heat dissipation from the switching element to the case is also efficient, and more efficient cooling becomes possible.

Further, the bottom wall of the case is a pair of a plate-shaped flat portion having two sides extending in parallel in one direction and a pair that bends in the same direction from the two sides of the flat portion, stands up, and then bends in a direction separated from each other. The switching element is abutted against the flat portion via an electrically insulating heat-dissipating sheet, and the plus and minus power lines are connected to the pair of steps via an adhesive. Since each portion is adhered to each other, the number of parts can be reduced by eliminating the need for a screw member or the like for fixing the substrate to the case. Moreover, the height of the stepped portion from the flat portion is smaller than the distance between the patterned surface of the positive and negative power supply lines and the protruding end surface of the switching element excluding the heat dissipation sheet from one surface of the substrate, so that the positive and negative parts are negative. It ensures that there is a gap between the power line and the step to fill the adhesive, and electrical insulation between the positive and negative power lines and the step of the case even if vibration or impact is applied to the case. It is possible to prevent breakdown and prevent electrical conduction between the positive and negative power lines and the case.

It is an overall perspective view of the driver for driving a motor. It is an exploded perspective view of the driver for driving a motor. It is a 3 arrow view of FIG. It is a cross-sectional view taken along line 4-4 of FIG. It is sectional drawing corresponding to FIG. 4 in the state which the inverter unit, the electronic control unit and the heat dissipation sheet are separated.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 5 attached. First, in FIGS. 1 to 3, the circuit board device is, for example, a motor drive driver for driving an electric motor of a drone. The inverter unit 11 that converts power from direct current to three-phase alternating current and the control unit 12 that controls the operation of the inverter unit 11 are housed and fixed in a metal case 13 that also serves as a heat sink.

The case 13 has a plate-shaped flat portion 38a having two sides extending in parallel in one direction 20, and the flat portion 38a is bent at a right angle in the same direction from the two sides, stands up, and then bends in a direction away from each other. It is configured in a box shape with a bottom wall 38 having a pair of stepped portions 38b.

The inverter unit 11 is mounted on the first substrate 14, the plus and minus power supply lines 15 and 16 printed on one surface 14a of the first substrate 14, and the one surface 14a of the first substrate 14. It includes at least six switching elements 17, such as FETs, and a pair of capacitors 18 mounted on the first substrate 14. The positive and negative power supply lines 15 and 16 are exaggerated in FIG. 3 for the sake of clarity.

The positive and negative power supply lines 15 and 16 extend in parallel to the one direction 20 at positions spaced apart from each other, and at both ends of the one surface 14a in a direction intersecting the one direction 20. It is printed on the first substrate 14 . Further , on the other surface 14b on the opposite side of the one surface 14a of the first substrate 14, positive and negative inputs are made so as to be connected to the positive and negative power supply lines 15 and 16 at one end of the one direction 20. The side conductors 21 and 22 are connected, and the other surface 14b of the first substrate 14 has three output side conductors 23, 24, for outputting three-phase alternating current at the other end of the one direction 20. 25 is connected.

The switching element 17 is mounted on the one surface 14a of the first substrate 14 so as to be arranged between the plus and minus power supply lines 15 and 16 so as to open a space between them . The pair of capacitors 18 are mounted on the first substrate 14 so as to be arranged between the connection portions of the plus and minus input side conductors 21 and 22 to the first substrate 14.

On the other hand, the control unit 12 is the first substrate 14 of the second substrate 27 supported via a plurality of connectors 26 also serving as support legs on the other surface 14b of the first substrate 14. On the surface 27a facing the opposite side, a plurality of operational amplifiers 28, one regulator 29, a plurality of capacitors 30, a microcomputer 31, and the like are mounted. The connector 26 does not protrude from the one surface 14a of the first substrate 14. Further, at one end of the surface 27a of the second substrate 27 facing the opposite side of the first substrate 14 along the one direction 20, a plurality of connecting portions 32 such that signal lines are connected by soldering are provided. A program rewriting device for rewriting the program of the microcomputer 31 at the other end of the surface 27a of the second substrate 27 facing the opposite side of the first substrate 14 along the one direction 20. A coupler 33 for connecting the solder is provided.

With reference to FIG. 4, the positive and negative power supply lines 15 and 16 on the one side 14a of the first substrate 14 are via an adhesive 36 which is a heat radiating member having electrical insulation and high thermal conductivity. The switching element 17 is brought into contact with the case 13 via a heat radiating sheet 37 having electrical insulation.

Specifically, the first substrate 14 is housed in the case 13 with the one surface 14a facing the inner surface of the flat portion 38a of the case 13, and the switching element 17 has electrical insulation. The positive and negative power supply lines 15 and 16 are brought into contact with the flat portion 38a via the heat radiating sheet 37, and the positive and negative power supply lines 15 and 16 are adhered to the pair of step portions 38b via the adhesive 36 , respectively.

With reference to FIG. 5, the positive and negative power supply lines 15 and 16 from the one surface 14a of the first substrate 14 to the protruding end surface 17a of the switching element 17 in a state where the heat dissipation sheet 37 is removed. The height H of the stepped portion 38b from the flat portion 38a is set smaller than the distance L from the pattern surface of the above.

Next, the operation of this embodiment will be described. The first substrate 14 in the inverter unit 11 is housed in the case 13 with one side surface 14a facing the inner surface of the case 13, at a position spaced apart from each other. The positive and negative power supply lines 15 and 16 printed on the one side surface 14a of the first substrate 14 so as to extend in parallel to the one direction 20 are heat-dissipating members having electrical insulation and high thermal conductivity. Since the case 13 is brought into contact with the case 13 via the adhesive 36, the positive and negative power supply lines 15 in which the currents flowing in the output side conductors 23 to 25 of each of the three output side conductors on the output side in the inverter unit 11 are averaged and flow. The heat from 16 can be efficiently radiated and cooled, and the output performance can be improved. Compared to the one with the same output, the physique of the motor drive driver is made smaller and lighter. be able to.

Further, since the switching element 17 is brought into contact with the case 13 via the heat radiating sheet 37 having electrical insulation, heat dissipation from the switching element 17 to the case 13 is also efficient, and more efficient cooling becomes possible. ..

Further, the positive and negative power supply lines 15 and 16 are printed on both ends of the one side surface 14a of the first substrate 14 so as to extend parallel to the one direction 20, respectively, and the case 13 is described. The bottom wall 38 facing the one surface 14a of the first substrate 14 has two sides extending in parallel to the one direction 20 and is in contact with the switching element 17 via the heat radiating sheet 37. And a pair of stepped portions 38b that are bent in the same direction from the two sides of the flat portion 38a and then bent in a direction that is separated from each other after standing up, and the plus and minus are provided via the adhesive 36. Since the power supply lines 15 and 16 of the above are adhered to the pair of stepped portions 38b, the number of parts can be reduced by eliminating the need for screw members or the like in order to fix the first substrate 14 to the case 13.

Further, from the distance L from the pattern surface of the positive and negative power supply lines 15 and 16 from the one surface 14a of the first substrate 14 to the protruding end surface 17a of the switching element 17 in a state where the heat radiation sheet 37 is removed. Also, since the height H of the stepped portion 38b from the flat portion 38a is set small, a gap for filling the adhesive 36 between the positive and negative power supply lines 15 and 16 and the stepped portion 38b is provided. It is formed securely, and even if vibration or shock is applied to the case 13, it prevents electrical insulation breakdown between the positive and negative power supply lines 15 and 16 and the step portion 38b of the case 13, and is positive. It is possible to prevent electrical conduction between the negative power supply lines 15 and 16 and the case 13.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and various design changes are made without departing from the present invention described in the claims. Is possible.

11 ... Inverter unit 13 ... Case 14 ... Board 14a ... One side of the board 15 ... Positive power supply line 16 ... Negative power supply line 17 ... Switching element 20 ... 1 Direction 36 ... Adhesive 37 ... Heat dissipation sheet 38 ... Bottom wall 38a ... Flat part 38b ... Step part H ... Height L ... Distance

Claims (5)

A substrate (14), positive and negative power lines (15, 16) printed on one surface of the substrate (14), and at least six switching elements mounted on one surface (14a) of the substrate (14). In a circuit board device in which an inverter unit (11) that converts power from direct current to three-phase alternating current while having (17) is housed and fixed in a metal case (13) that also serves as a heat sink.
After the case (13) rises by bending in the same direction from the plate-shaped flat portion (38a) having two sides extending in parallel in one direction (20) and the two sides of the flat portion (38a). It comprises a bottom wall (38) with a pair of steps (38b) that bend in a direction away from each other.
The substrate (14) is housed in the case (13) with the one surface (14a) facing the inner surface of the flat portion (38a) of the case (13), and the switching element (17) is electrically insulated. It is abutted against the flat portion (38a) via the heat radiating sheet (37) having a property, and is brought into contact with the flat portion (38a).
The plus and minus are printed on both ends of the one surface (14a) of the substrate (14) in a direction intersecting the one direction (20) so as to extend parallel to the one direction (20), respectively . The power supply lines (15, 16) of the above are adhered to the pair of steps (38b) via an adhesive (36) having electrical insulation and high thermal conductivity, respectively.
The positive and negative power supply lines (15, 16) from the one surface (14a) of the substrate (14) to the protruding end surface (17a) of the switching element (17) in a state where the heat dissipation sheet (37) is removed. A heat dissipation structure in a circuit board device , wherein the height (H) of the step portion (38b) from the flat portion (38a) is set smaller than the distance (L) from the pattern surface of the above . The first aspect of the present invention is characterized in that the step portion (38b) is bent at a right angle from the two sides of the flat portion (38a) and rises, and the substrate (14) is supported by the step portion (38b) . The heat dissipation structure in the circuit board device described. The heat dissipation structure in the circuit board device according to claim 1 or 2, wherein a space is formed between the switching elements (17) . A connector (26) connected to the substrate (14) at both ends of the substrate (14) on a surface (14b) opposite to the one surface (14a) in a direction intersecting the one direction (20). The heat dissipation structure in the circuit board apparatus according to any one of claims 1 to 3, wherein the connector (26) does not protrude from the one surface (14a) of the substrate (14). .. The claim is characterized in that a second substrate (27) connected to the connector (26) is arranged on the upper surface of the substrate (14) so as to be supported by the connector (26). The heat dissipation structure in the circuit board apparatus according to 4.

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