JP2008160962A - High-temperature operation motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-temperature operation motor wherein the temperature of a junction in IC mounted on PCB does not exceeds a service temperature limit even in an environment at a high temperature of 80° or above. <P>SOLUTION: The PCB 13 mounted with the IC 11 and other electronic components is fit to the peripheral portion of a base 8, and is disposed so that the PCB is sandwiched between the base 8 and an upper yoke 2. A heat radiation pattern 17 is formed on the opposite surface of the PCB 13. The pattern on the electronic component side where the IC 11 and the like are mounted and connected is thermally connected to the heat radiation pattern 17 through a through hole 16. As a result, the heat radiation area on the PCB 13 is increased, and thus it is possible to control the temperature of a junction in the IC to a value equal to or lower than a service temperature limit in a high-temperature environment and to normally operate the IC. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a high temperature operation motor that enables normal operation of an IC in a high temperature environment by efficiently radiating heat generated from an IC such as a motor driver mounted on a printed circuit board (PCB).

There is a demand to use a fan motor at a higher ambient temperature (105 ° C) than before. In order to answer this requirement, the motor driver IC must operate normally at an environmental temperature of 105 ° C. In order for the motor driver IC to operate normally at a high temperature, it is necessary to suppress an increase in the junction temperature of the IC.
8 and 9 show the structure of a conventional fan motor.
A bearing housing 10 is fixed to the base 8, and a coil 6 is attached to the outer periphery of the bearing housing 10. The upper yoke 2 is disposed so as to cover the upper surface and the outer peripheral surface of the coil 13, and the lower surface yoke 3 is disposed so as to cover the lower surface of the coil 13.

The PCB 41 is fitted on the outer periphery of the bearing housing 10 and is disposed between the lower surface of the base portion 8 and the upper surface of the upper yoke 2. A magnet 5 is attached to the inner wall of the bottomed cylindrical rotor portion 4, and a shaft 15 fixed to the center of the rotor portion 4 is rotatably fitted into a bearing 7 in the bearing housing 10.
A PCB pattern 42 is formed on the upper surface of the PCB 41, and an IC 11 such as a motor driver is connected between the lands of the pattern 42 by soldering. In addition, electronic components constituting the drive circuit are mounted (not shown).

  The heat generated from the IC 11 in this motor has a structure in which heat is released from the IC pin 12 and the pattern (copper) on the electronic component mounting side where the IC pin 12 is soldered. This structure has no problem with respect to the heat dissipation effect at the conventional environmental temperature (about 80 ° C. or less). However, when used in a high temperature environment of 80 ° C. or higher (eg, 105 ° C.), there is a problem that the junction temperature inside the IC exceeds the use limit and the IC does not operate normally.

Patent Documents 1 and 2 have been proposed as a motor structure provided with a mechanism for releasing heat generated by electronic components mounted on a substrate.
Patent Document 1 discloses a structure for cooling a drive IC (electronic component) in which a drive IC of a DC brushless motor is exposed from a stator and a heat sink is attached.
In addition, the fan structure of Patent Document 2 has a circuit element region and a heat dissipation film on which a heat generating element is mounted on one surface of the substrate, disposes the heat generating element near the circuit element region, and dissipates heat using the heat dissipation film. It is comprised as follows.
JP 2002-223553 A JP 2004-319949 A

However, Patent Document 1 is a structure in which a heat radiating plate is attached to the exposed heat radiating portion of a driving IC mounted on a driving P plate using screws, and a structure capable of efficiently radiating a large number of electronic components in a high temperature environment. In addition, there is a problem that mounting structures must be provided as many as the number of semiconductor elements that require heat dissipation.
Further, since Patent Document 2 must have a structure in which a part of the heat generating element protrudes outside the circuit element region and is connected to a part of the heat generating element, the plurality of electronic components each reach the heat dissipation film. There is a problem that the cooling structure for operating the IC normally in a high temperature environment becomes complicated due to restrictions on the arrangement of each electronic component.

  The present invention has been made in view of the above circumstances, and its purpose is to provide a high-temperature operating motor in which the junction temperature inside the IC mounted on the PCB does not exceed the use limit even when used in a high-temperature environment of 80 ° or more. It is to provide.

In order to achieve the above object, claim 1 of the present invention provides a fan motor having a structure in which a printed circuit board on which electronic components for driving a motor are mounted is mounted on a yoke having a coil therein. A heat radiation pattern is formed on the opposite surface (lower surface), the electronic component mounting side pattern of the printed circuit board and the heat radiation pattern are thermally coupled by a through hole, and the heat generated by the electronic component is also radiated from the heat radiation pattern. It is characterized by.
According to a second aspect of the present invention, in the first aspect of the present invention, a heat radiating plate is thermally coupled to the heat radiating pattern on the opposite surface of the printed circuit board.
According to a third aspect of the present invention, in the first or second aspect of the present invention, a heat sink is thermally coupled to the electronic component mounting side pattern of the printed circuit board.
According to a fourth aspect of the present invention, in the invention according to the second or third aspect, the shape of the heat radiation pattern on the opposite surface of the printed circuit board is formed larger than the outer dimension of the board, and the wind of the fan is applied to the protruding portion of the heat radiation pattern. Thus, the heat dissipation characteristics are improved.

  According to the above configuration, a sufficient heat radiation area can be secured on the upper and lower surfaces of the PCB, an increase in the junction temperature inside the IC can be suppressed, and a high temperature operation motor can be realized.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a sectional view showing an embodiment of a high temperature operation motor according to the present invention.
Since the rotor part 4, the yoke 2, 3, the magnet 5, the shaft 15, the bearing 7, the bearing housing 10, and the base part 8 in this embodiment are not different from the configuration of FIG. 8, description of these parts is omitted.
A PCB pattern 14 for mounting an electronic component such as the IC 11 is provided on the upper surface of the PCB 13. A heat radiation pattern 17 is formed on the opposite surface of the PCB 13. The heat radiation pattern 17 on the opposite surface to the PCB pattern 14 on the upper surface of the PCB 13 is thermally connected by a through hole 16.

FIG. 2 is a partial cross-sectional view for explaining the heat radiation of the PCB of the high temperature operation motor of FIG.
A part of the heat generated from the IC 11 is directly radiated from the IC pin 12, and the remaining heat is conducted to the PCB pattern 14 on the opposite surface of the PCB 13 through the IC pin 12. Further, the heat is transmitted to all of the heat radiation patterns 17 on the opposite surface of the PCB 13 through the through holes 16, and the heat generated by the IC 11 is radiated from the respective patterns on the upper and lower surfaces of the substrate.
In this way, the PCB 13 is a double-sided pattern substrate, and the heat radiation area is reduced by using a structure in which the pattern on the surface opposite to the electronic component (IC) mounting surface and the pattern on the electronic component mounting surface are thermally coupled by through holes. By increasing the temperature, the junction temperature in a high temperature environment can be kept below the usable limit.

FIG. 3 is a partial sectional view showing a second embodiment of the substrate portion of the high temperature operation motor according to the present invention.
In this embodiment, a lower surface heat radiation plate (AL, Cu, etc.) 18 having good thermal conductivity is provided on a heat radiation pattern 17 on the lower surface of the lower PBC 13 via a heat coupling member 19.
In addition to the structure shown in FIG. 2, a lower surface heat radiation plate 18 having good thermal conductivity is thermally coupled to the surface opposite to the pattern of the electronic component mounting surface to further increase the heat radiation effect.

FIG. 4 is a partial sectional view showing a third embodiment of the substrate portion of the high temperature operation motor according to the present invention.
In this embodiment, an upper surface heat sink 20 is provided on a part of the PCB pattern 14 on the upper surface of the PCB 13 via a heat coupling member 21.
In addition to the structure of FIG. 2 described above, the heat radiation effect is further improved by thermally bonding the upper surface heat sink 20 with a material having good thermal conductivity on the pattern of the electronic component mounting surface.
FIG. 5 shows an example of the heat coupling member 19 between the heat radiation pattern 17 and the lower surface heat radiation plate 18.
Solder, thermal grease, thermal compound or the like is used as the thermal coupling member 19.

FIG. 6 is a partial cross-sectional view for explaining an example of a member that replaces the through hole that thermally couples the upper and lower surfaces of the PCB.
As an application example, an effect equivalent to that of the present invention can be obtained even if a hole is provided in a PCB instead of a through hole, and a metal piece 22 such as a wire is connected to an upper pattern and a lower pattern with solder.
FIG. 7 is a partial cross-sectional view for explaining an example of a heat dissipation method of the heat dissipation substrate.
The size of the outer shape of the heat sink 32 provided on the surface of the PCB 31 opposite to the mounting surface of the electronic component 30 is made larger than the outer shape of the PCB 31, and the air flow from the fan 33 is applied to the outer periphery of the heat sink 32. Is. Thereby, heat dissipation can be further improved.

With the above configuration, the internal temperature increase of the motor driver IC can be reduced, and the upper limit of the operating temperature range of the IC can be increased more than before.
The present applicant has proposed an invention of a fan motor with a heat sink that reduces the temperature rise of the coil in contact with the stator yoke and lowers the bearing temperature by attaching a metal plate with good heat dissipation directly under the stator yoke. (Japanese Patent Application No. 2005-329191).
The internal temperature of the IC can be obtained by thermally bonding the pattern of the surface opposite to the electronic component mounting surface of the present invention to the stator yoke of the proposed motor or by bonding it with a material having good thermal conductivity. The rise and coil temperature rise can be suppressed simultaneously.

  This is a fan motor that can be used in a high temperature environment.

It is sectional drawing which shows embodiment of the high temperature operation motor by this invention. It is a fragmentary sectional view for demonstrating heat dissipation of PCB of the high temperature operation motor of FIG. It is a fragmentary sectional view which shows 2nd Embodiment of the board | substrate part of the high temperature operation motor by this invention. It is a fragmentary sectional view which shows 3rd Embodiment of the board | substrate part of the high temperature operation motor by this invention. It is a fragmentary sectional view for demonstrating the coupling structure of a heat sink and a substrate pattern. It is a fragmentary sectional view for demonstrating the example of the member replaced with the through hole which couple | bonds a PCB upper and lower surface thermally. It is a fragmentary sectional view for explaining an example of the heat dissipation method of a heat dissipation board. It is sectional drawing for demonstrating the thermal radiation structure of the conventional fan motor. It is a fragmentary sectional view for demonstrating the heat dissipation method of the conventional fan motor.

Explanation of symbols

1 Motor
2 Upper yoke 3 Lower yoke
4 Rotor part
5 Magnet
6 Coil 7 Bearing 8 Base 9 Fan 10 Bearing Housing 11 IC (Integrated Circuit)
12 IC pin 13 Printed circuit board (PCB)
14 PCB pattern 15 Shaft 16 Through hole 17 Heat radiation pattern 18 Lower surface heat sink 19, 21 Thermal coupling member 20 Upper surface heat sink

Claims (4)

In a fan motor having a structure in which a printed circuit board on which electronic components for driving a motor are mounted on a yoke having a coil inside,
A heat dissipation pattern is formed on the opposite surface of the printed circuit board, the electronic component mounting side pattern of the printed circuit board and the heat dissipation pattern are thermally coupled by a through hole, and the heat generated by the electronic component is also dissipated from the heat dissipation pattern. A high-temperature operating motor characterized by   2. A high-temperature operating motor according to claim 1, wherein a heat radiating plate is thermally coupled on a heat radiating pattern opposite to the printed circuit board.   The high-temperature operation motor according to claim 1 or 2, wherein a heat sink is thermally coupled to the electronic component mounting side pattern of the printed circuit board.   3. A heat radiation characteristic is improved by forming a heat radiation pattern on the opposite surface of the printed circuit board larger than an outer dimension of the board and applying a fan wind to a protruding portion of the heat radiation pattern. Or the high temperature operation motor of 3.

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