JPH04347568A - Brushless motor - Google Patents

Abstract

PURPOSE:To easily obtain a highly reliable and ultraminiature brushless motor by remarkably reducing wire bonding process and introducing hall elements and drive coils within an IC. CONSTITUTION:Hall elements 10 for detecting position of rotor magnet 2, drive coils 11 and control circuits 9 for controlling flowing current according to the position of rotor are constituted on one or a plurality of integrated circuits.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless motor, and more particularly to a brushless motor suitable for ultra-small motors called millimeter motors and micromotors.

0002

[Prior Art] Conventionally, when an ultra-small motor is used in the configuration, as shown in FIG. Direct bonding (wire bonding 22) with the chip intact, and drive coil 2.
3 is made of a copper foil pattern on a printed circuit board 24, and a Hall element 26 for detecting the position of the magnet 25 is also wire bonded 22 on this printed circuit board 24 in the same way as the IC.
to configure a brushless motor. In this configuration, there are many wire bondings for connecting mutual elements, which makes assembly time-consuming and poses a problem in reliability.

[0003] The rotor is rotatably supported by a magnet 25 and a yoke 27 together with a rotating shaft 28 on both sides of a printed circuit board 24 on which the drive coil 23 is disposed. 28 is a support member that supports the rotating shaft 28 disposed in the stator. The other parts are larger than the rotor, making it a rather large motor to be called an ultra-compact motor.

0004

SUMMARY OF THE INVENTION The present invention has been made in order to solve the problems and drawbacks of the conventional art. The challenge is to easily obtain a highly reliable and ultra-small motor by incorporating the drive coil into an IC.

[0005]

[Means for Solving the Problems] The brushless motor of the present invention includes a detector for detecting the position of a rotor magnet, a drive coil, and a circuit for controlling the current flowing through the coil depending on the rotor position, on one or more integrated circuits. It is characterized by being configured as follows. In this brushless motor, the yoke constituting the magnetic circuit is formed by forming a film of a material with low magnetic resistance on the integrated circuit.

Furthermore, this brushless motor is characterized in that a portion made of a material that is resistant to sliding is provided on the integrated circuit, and the rotor rotation shaft is supported by this portion.

[0007]

[Operation] By doing this, wire bonding can be greatly reduced and the Hall element and drive coil can be connected to the IC.
This makes it possible to achieve high reliability and ultra-miniaturization.

[0008]

[Embodiment] The present invention attempts to configure electrical elements such as a drive circuit, a Hall element for position detection, and a drive coil necessary for constructing an ultra-small motor on one integrated circuit. It is. Examples of the present invention are shown below in FIGS. 1 to 6.
Explain with reference to. FIG. 1 shows the appearance of the brushless motor of this invention. 1 in which electrical elements such as a drive circuit, a Hall element for position detection, and a drive coil are configured.
One integrated circuit (IC) 1 is placed between two magnets 2, and the magnets 2 are connected by a rotating shaft 3, and the rotating force generated between the magnet 2 and the drive coil is transferred to the rotating shaft 3. I'm taking it out. The power supply and control terminals are drawn out from the IC using wire bonding 4 and are connected to terminals 5.
connected to. 6 represents a yoke, and 7 represents a support member.

FIGS. 2 and 3 show the inside of the IC. Figure 2 shows I
FIG. 3 is an enlarged view of C, and FIG. 3 is a cross-sectional view of the IC. On the IC,
A power transistor 8 for switching the current flowing through the coil and a control circuit 9 for controlling the power transistor 8 are constituted by means forming an ordinary integrated circuit. Furthermore, the Hall element 10 for position detection is also constructed by the same means, and the magnet 2
They are arranged in a predetermined phase relationship at a position where the magnetic field can be detected. Drive coil 11 is constructed using aluminum wiring that is used to connect elements on an IC.

FIG. 3 shows a cross section of the IC part where the drive coil 11 is arranged. Elements such as a transistor 12 and a resistor 13 are connected to a first layer of aluminum wiring 14, and on top of that, an aluminum wiring 14 is connected. A second layer of aluminum wiring 14 is formed with an insulating layer 15 in between, forming a spiral drive coil as shown in FIG. 16 indicates a P-type semiconductor substrate. FIG. 4 shows a bearing in the thrust direction formed on an IC chip, and FIG. 5 is a partially enlarged cross-sectional view of section A in FIG. By forming a sliding material that can withstand the rotational sliding of the rotating shaft 3 as the bearing material 17 on the IC chip during the IC process, further miniaturization can be achieved.

In FIG. 6, an iron-based yoke material 18 is formed under the drive coil on the IC chip during the IC process in order to concentrate the magnetic flux in the drive coil and improve drive efficiency.

0012

[Effects of the Invention] As explained above, the brushless motor of the present invention can significantly reduce wire bonding, and furthermore, by incorporating the Hall element and the drive coil into the IC, it is highly reliable and ultra-compact. A motor can be easily realized.

[Brief explanation of drawings]

[Fig. 1] External view of the brushless motor of this invention

[Figure 2]
Enlarged view of IC of this invention

[Figure 3] Internal cross-sectional view of the IC of this invention

[Figure 4] External view of a thrust direction bearing formed on the IC chip of this invention

[Fig. 5] Partially enlarged sectional view of part A in Fig. 4

[Figure 6] Cross-sectional view of an IC using the yoke material that collects magnetic flux of the present invention

[Figure 7] External view of a conventional brushless motor

[Explanation of symbols]

1 Integrated circuit (IC) 2. Magnet 3 Rotation axis 4 Wire bonding 5 Pull-out terminal 6 York 7 Support material 8 Power transistor 9 Control circuit 10 Hall element 11 Drive coil 12 Transistor 13 Resistance 14 Aluminum wiring 15 Insulating layer 16 P-type semiconductor substrate 17 Bearing material

Claims (3)

[Claims] 1. A brushless motor characterized in that a detector for detecting the position of a rotor magnet, a drive coil, and a circuit for controlling a current flowing through the coil depending on the rotor position are configured on one or more integrated circuits. 2. The brushless motor according to claim 1, wherein the yoke constituting the magnetic circuit is formed by forming a film of a material with low magnetic resistance on the integrated circuit. 3. The brushless motor according to claim 1, wherein a part added with a material suitable for sliding is provided on the integrated circuit, and the rotor's rotating shaft is supported by the part. .