JPH0736465Y2 - Electronic component heat dissipation structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a heat dissipation structure for electronic parts in a transistor motor or the like.

[Problems to be solved by conventional techniques and devices]

Generally, as this type of electronic component heat dissipation structure, for example, an electronic component such as an IC or a transistor is attached to a heat dissipation plate (heat sink) made of a block of metal such as aluminum having a large thermal conductivity. The heat generated by the electronic component is absorbed by the air, and the heat is exchanged by the air contacting the surface of the heat radiating plate. Therefore, in order to improve the cooling effect, it is necessary to increase the size of the heat dissipation plate composed of the block to enhance the heat exchange capacity, which increases the volume of the entire apparatus and reduces the size of the block.
The cooling effect will be poor.

Further, conventionally, a structure is also known in which blades (fins) are provided on a rotor of a motor so as to project to cool the heat radiating plate (or electronic component), but it is difficult to balance the rotor dynamically, and There is a drawback that noise due to the wind noise caused by is likely to occur, and there is a problem that the cost is further increased.

Therefore, an object of the present invention is to provide an electronic component heat dissipation structure that can reduce the size of the heat dissipation plate (heat sink) and has an excellent cooling effect.

[Means for Solving the Problems]

In order to achieve the above-mentioned object, the electronic component heat dissipation structure of the present invention mounts an electronic component that easily generates heat on a circuit board that rotatably supports a rotor of a motor, and contacts the electronic component with a heat sink. And a heat sink parallel to the rotor axis is formed on this heat sink, and at least a part of the heat sink is located in the boundary layer generated by the rotation of the rotor around the smooth outer peripheral surface of the rotor. It was made to let.

[Action]

The air in contact with the outer peripheral surface of the rotating rotor rotates together with the rotor due to its viscosity, and a so-called boundary layer is generated. By bringing the heat dissipating piece closer to the boundary layer, the air contacting the heat dissipating piece moves, and the amount of contact air having a temperature difference from the heat dissipating piece increases. Therefore, the amount of heat that can be released from the heat dissipating piece is increased, so that the heat dissipating effect is improved and the electronic component can be sufficiently cooled.

〔Example〕

 The present invention will be described below based on the illustrated embodiments.

In FIGS. 1 and 2, reference numeral 1 is a circuit board, and a fixed shaft 2 of a motor is fixed to the circuit board 1 via a bush 3 and the like. Reference numeral 4 denotes a rotor of the motor. The rotor 4 is a smooth surface having no blades (fins) on its outer peripheral surface, and is rotatably pivoted around a fixed shaft 2 via a bearing (not shown). While being worn, a rotor magnet (not shown) is internally fitted to a part of the inner surface thereof.
In addition, a stator (not shown) that closely faces the rotor magnet is fixed to the fixed shaft 2. And
5 is an electronic component such as an IC and a transistor, and a circuit board
It is fitted in the through hole 6 provided in the. Also, the electronic component 5
Has a hole 8 through which the tightening member 7 can be inserted, and a hole 9 communicating with the hole 8 is formed in the circuit board 1. Denoted at 10 are lead portions which penetrate the circuit board 1 and are fixed thereto.

Reference numeral 11 denotes a heat dissipation plate made of aluminum or the like, and a hole 12 is formed at the base end of the heat dissipation plate 11, and the tightening member 7 is inserted through the hole 12 and the holes 8 and 9. The heat sink 11, the electronic component 5, and the circuit board 1 are integrally fixed. And the heat sink
A heat radiating piece is provided at the tip of 11 so as to approach the rotor 4.
13 are extended. In this case, the heat dissipating piece 13 was extended in the radial direction of the rotor 4 by bending, but as shown in FIG. 3, the heat dissipating piece 13 was extended obliquely with respect to the radial direction-that is, in the tangential direction. It is desirable to extend.

FIG. 4 shows another embodiment in which the circuit board 1 does not have the through hole 6, and other configurations are the same as those in the embodiment of FIG.

FIG. 5 shows still another embodiment. The heat dissipation plate 11 is a hollow box type, and the heat dissipation piece 13 extends from one corner of the heat dissipation plate 11. The electronic component 5 is fixed to one side surface of the box-shaped heat dissipation plate 11. In this case, if a vent hole is formed on each side, the heat dissipation effect is further improved.

Then, when the rotor 4 rotates, a boundary layer is generated around the rotor 4 due to the viscosity of the air itself, and the heat radiating piece 13 approaching and approaching to the boundary layer is deprived of heat by the air in the boundary layer moving while making contact. To be cooled. As described above, although the outer peripheral surface of the rotor 4 is a smooth surface (without conventional blades), the heat dissipation plate 13 cools the heat dissipation plate 11, and accordingly heat is taken from the electronic component 5. As a result, the electronic component 5 is sufficiently cooled.

It should be noted that the present invention is not limited to the above-described embodiments, and design changes can be freely made without departing from the gist of the present invention. For example, in the above-described embodiment, the heat dissipation piece 13 is indirectly connected to the electronic component 5 via the heat dissipation plate 11, but the heat dissipation piece 13 may be directly connected to the electronic component 5 as well. . Furthermore, it is possible to provide a recess or the like at the tip of the heat dissipating piece 13 so that the air flow associated with the rotation of the rotor 4 can be brought into contact with the heat dissipating piece 13 more easily. Further, the motor may be of the shaft rotation type. Further, in the embodiment shown in FIGS. 1, 3, and 4, the heat sink 11
It is also desirable to extend the base end portion of so as to cover the upper surface of the electronic component 5.

[Effect of device]

Since the present invention is configured as described above, it has the great practical effects described below.

At least a part of the heat dissipation plate of the heat dissipation plate attached in contact with the electronic component is located in the boundary layer around the outer peripheral surface of the rotor. The amount of heat that can be released from the
The heat dissipation effect is improved and the electronic parts can be cooled sufficiently.

Since the heat dissipation piece is formed parallel to the axis of the rotor,
The air moving by the rotation of the rotor can be effectively applied to the heat radiating piece, the cooling effect of the heat radiating piece can be sufficiently increased, and the heat radiating plate and the like can be made compact as a whole.

Even if the outer peripheral surface of the rotor is smooth, it is possible to effectively cool the electronic components, so there is no need to provide complicated blades (fins), the manufacturing cost can be reduced, and dynamic imbalance of the rotor and Therefore, the wind noise due to the fins is not generated, and the generation of vibration and noise can be prevented.

[Brief description of drawings]

FIG. 1 is a partially sectional front view showing an embodiment of the present invention, and FIG.
FIG. 5 is a plan view, FIG. 3 is a plan view showing another embodiment, FIG. 4 is a partial sectional front view showing yet another embodiment, and FIG. 5 is a plan view showing yet another embodiment. . 4 ... Rotor, 5 ... Electronic parts, 13 ... Radiation piece.

Claims (1)

[Scope of utility model registration request] 1. An electronic component radiating structure for radiating heat of an electronic component, which is apt to generate heat, mounted on a circuit board that rotatably supports a rotor of a motor, wherein a radiating plate is attached to the electronic component in contact therewith. , A radiating piece parallel to the axis of the rotor is formed on the radiating plate,
An electronic component heat dissipation structure in which at least a part of the heat dissipation piece is located in a boundary layer generated by rotation of the rotor around a smooth outer peripheral surface of the rotor.