JPH065376U - Brushless motor - Google Patents

Abstract

(57) [Summary] [Object] To provide a brushless motor that is inexpensive and has a high component mounting process efficiency, and that has a sufficient heat dissipation effect while keeping the component mounting height low. [Structure] The drive circuit IC1 is surface-mounted on a printed circuit board 3, and the mounting surface of the printed circuit board 3 is at a position higher than the lower surface of the IC package. In the drive circuit IC1, a part of the package is embedded in a hole provided in the printed circuit board 3, and a heat radiating metal plate on the lower surface of the package is brought into contact with the stator yoke 4 to conduct heat generation, thereby reducing the mounting height of the IC. At the same time, a sufficient heat radiation effect is obtained by the stator yoke 4.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a brushless motor having a drive circuit IC surface-mounted on a printed circuit board.

[0002]

[Prior art]

 In recent years, miniaturization of IC encapsulation packages has progressed, and many packages for surface mounting have been used. In particular, for the IC mounted inside the motor, the surface mountable package is increasingly used due to the demand for miniaturization. However, ICs used in motors require relatively large permissible power consumption, so some ingenuity was required for mounting. The heat dissipation structure of the conventional brushless motor drive circuit IC will be described below.

FIG. 4 shows a heat dissipation structure of a conventional drive circuit IC. Reference numeral 1 is a drive circuit IC, and 2 is a metal base printed circuit board. Such a structure is generally used because it has an efficient structure because the metal-based printed circuit board performs both electrical wiring and heat dissipation at the same time. Further, FIG. 5 shows another example of the conventional heat dissipation structure of the drive circuit IC. In FIG. 5, 1 is a drive circuit IC, 3 is a printed circuit board, 4 is a stator yoke, and a raised portion corresponding to the thickness of the printed circuit board is provided at a position where the package of the drive circuit IC1 comes. Reference numeral 5 is a mounting screw. A hole is formed in the printed circuit board 3 at a position where the package of the drive circuit IC1 comes, and by inserting the raised portion of the stator yoke 4 into this hole, the drive circuit IC1 and the stator yoke 4 are brought into contact with each other and a mounting screw is attached. It is configured to radiate heat by tightening with. Reference numeral 8 is a set mechanism, and reference numeral 9 is another printed circuit board used in this set.

[0004]

[Problems to be solved by the device]

 However, in the conventional configuration shown in FIG. 4, an expensive metal-based printed circuit board is required, and the metal-based printed circuit board is formed by connecting a number of printed circuit boards of the same shape to each other and then dividing them into individual parts. Since it is extremely difficult to use this assembly method, electronic components must be mounted on each individual board. Therefore, there is a problem that it takes time to mount electronic components. Further, in the conventional configuration shown in FIG. 5, the mounting height of the drive circuit IC is increased by the thickness of the printed circuit board, so the space is insufficient and another printed circuit board 9 used for this set is placed around the motor. There was a problem that it could not be placed.

The present invention solves the above-mentioned problems of the related art, and uses a component that is inexpensive and has a short component mounting time, and a sufficient heat dissipation effect can be obtained while keeping the component mounting height of the IC mounting portion low. It aims at providing the brushless motor of.

[0006]

[Means for Solving the Problems]

 In order to achieve this object, the brushless motor of the present invention has a printed circuit board on which a drive circuit IC is mounted and a printed circuit board that closely adheres to the printed circuit board and extends the printed circuit board so as to face the rotor magnet and to face the magnetic flux path of the rotor magnet. An axial air gap type brushless motor including a flat plate-shaped stator yoke, the drive circuit IC including a terminal portion, a package, and a heat dissipation metal plate fixed to the package lower surface, and the package lower surface. Is located below the mounting surface of the terminal portion on the printed circuit board, and the printed circuit board has holes through which the package of the drive circuit IC can pass.

[0007]

[Action]

 With the above configuration, the lower surface of the package of the mounted drive circuit IC contacts the stator yoke through the hole of the printed circuit board, and the heat generated by the drive circuit IC is conducted to the stator yoke through the metal plate for heat dissipation.

[0008]

【Example】

 (Embodiment 1) An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, 1 is a surface-mounted drive circuit IC, 3 is a printed circuit board, 4 is a stator yoke, and 5 is a mounting screw. The mounting surface of the terminal portion of the drive circuit IC1 on the printed circuit board 3 is located higher than the lower surface of the package. The drive circuit IC is surface-mounted on the printed circuit board 3 with a hole in which a heat radiating metal plate on the lower surface of the package is fixed, and a part of the package is embedded in the hole of this printed circuit board and the heat radiation on the lower surface of the package is performed. The metal plate for use is in contact with the stator yoke 4. The drive circuit IC 1 and the stator yoke 4 are fastened with mounting screws in order to increase the degree of adhesion between the two metals and improve heat conduction.

As described above, in the brushless motor of the present embodiment, the heat generated by the drive circuit IC1 is directly transmitted to the status yoke 4, so that a printed circuit board made of paper phenol or the like can be used. Since an assembly method is possible in which a printed circuit board with a large number of connections is created and the electronic circuit board is mounted and then the printed circuit board is divided into individual pieces, the time required for the electronic component mounting process can be greatly reduced.

Further, since a part of the IC package is embedded in the hole provided in the printed circuit board 3, there is also an effect that the mounting height of IC can be kept low.

As described above, according to the present embodiment, the drive circuit IC1 includes the metal plate for heat dissipation fixed to the lower surface of the package, and the lower surface of the package is below the mounting surface of the printed circuit board 3, Has a hole through which the package of the drive circuit IC1 can pass, the lower surface of the package of the mounted drive circuit IC1 contacts the stator yoke 4 through this hole, and conducts heat to the stator yoke 4 through the metal plate for heat dissipation.

Second Embodiment A second embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a sectional view of another embodiment of the present invention. Parts having the same functions as in FIG. 1 are given the same numbers. 6 is a viscoelastic material or adhesive having high thermal conductivity. In FIG. 2, a viscoelastic material or adhesive 6 having a high thermal conductivity is sandwiched between the heat radiating metal plate of the drive circuit IC1 and the stator yoke 4 to be deformed, so that the contact area is widened. The thermal conductivity between the two metals can be increased without tightening, and a sufficient heat radiation effect can be obtained.

Third Embodiment A third embodiment of the present invention will be described below with reference to the drawings. FIG. 3 is a sectional view of another embodiment of the present invention. Parts having the same functions as in FIG. 1 are given the same numbers. Reference numeral 7 is a metal leaf spring or a filler such as metal fiber or foil. In FIG. 3, a metal leaf spring or a filler 7 such as metal fiber or foil is elastically or plastically deformed by being sandwiched between the heat radiating metal plate of the drive circuit IC1 and the stator yoke 4, and the metal Since it comes into contact with the metal, the thermal conductivity between the two metals can be increased without tightening from the outside, and a sufficient heat radiation effect can be obtained.

[0014]

[Effect of device]

 As described above, the present invention obtains good cooling by bringing the heat radiating metal plate of the drive circuit IC into contact with the stator yoke and conducting heat generation. Further, the cost is low and paper phenol or the like which is efficient in the electronic component mounting process is used. It is possible to reduce the mounting height of an IC while using a printed circuit board, and to provide an excellent brushless motor.

[Brief description of drawings]

FIG. 1 is a sectional view of a brushless motor according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a brushless motor according to a second embodiment of the present invention.

FIG. 3 is a sectional view of a brushless motor according to a third embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a heat dissipation structure of a conventional brushless motor IC.

FIG. 5 is a sectional view showing another heat dissipation structure of a conventional brushless motor.

[Explanation of symbols]

 1 Drive Circuit IC 3 Printed Circuit Board 4 Stator Yoke 6 Viscoelastic Material or Adhesive with High Thermal Conductivity 7 Metal Leaf Spring or Metal Fiber, Filler such as Foil

Claims (3)

[Scope of utility model registration request] 1. A printed circuit board on which a drive circuit IC is mounted,
In the brushless motor of the axial gap type, which closely supports the printed circuit board and extends the printed circuit board to face the rotor magnet, and a flat plate-shaped stator yoke that forms a magnetic flux path of the rotor magnet, the drive circuit IC Is provided with a terminal portion, a package, and a heat-dissipating metal plate fixed to the lower surface of the package, and the lower surface of the package is below the mounting surface of the terminal portion on the printed circuit board. A brushless motor that has a hole through which the package lower surface of the mounted drive circuit IC comes into contact with the stator yoke through this hole and conducts the heat generated by the drive circuit IC to the stator yoke through the metal plate for heat dissipation. 2. The brushless motor according to claim 1, further comprising a viscoelastic material having a high thermal conductivity or an adhesive which is interposed between the heat radiating metal plate and the stator yoke. 3. A brushless motor according to claim 1, further comprising a metal leaf spring inserted between the heat radiating metal plate and the stator yoke, or a filler such as metal fiber or foil.