JPH084382B2 - Brushless motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention has a printed circuit board fixed to the opposite surface of a stator yoke, and has a Hall element at a position corresponding to the inner space of the inner frame of the drive coil of the printed circuit board. Is arranged and connected, and the hall element and the magnet are directly opposed to each other through a through hole formed at a position corresponding to the hall element of the stator yoke, so that the hall element is attached to the drive coil. Place and connect to a place different from the surface,
The present invention relates to a brushless motor with improved yield and reduced size.

[Conventional technology]

A conventional brushless motor is shown in FIG. In FIG. 3, 1 is a magnet for driving, which is polarized by N and S alternately in the circumferential direction, 2 is a magnet yoke, 3 is a printed circuit board, 4 is a stator yoke, 5 is a drive coil, and 6 is a rotor. It is a Hall element for position detection. The magnet 1 and the magnet yoke 2 are fixed to the rotary shaft 8 together with the pulley 7 so that they can rotate freely, and a rotor portion is formed from them. The printed circuit board 3 is fixed to the facing surface of the stator yoke 4 facing the rotor portion, the drive coil 5 and the Hall element 6 are fixedly arranged on the printed circuit board 3, and electrically connected,
These form the stator part. As shown in FIG. 4, three Hall elements 6 and six drive coils 5 are formed to form a three-phase drive structure.

In FIG. 3, 9 is a bearing and 10 is a housing.

The magnetic flux emitted from the magnet 1 passes through the air gap in which the drive coil 5 and the Hall element 6 are arranged, reaches the stator yoke 4, and returns to the magnet 1 through the air gap again, forming a magnetic loop. .

[Problems to be solved by the invention]

In this conventional technique, since the Hall elements 6 are arranged at the center of the drive coil 5, respectively, when the land for the coil terminal exists at the center of the drive coil 5,
Since the hall element 6 is avoided, the land becomes small and soldering becomes difficult, and the terminals of the drive coil 5 are easily short-circuited with the terminals of the hall element 6, resulting in a decrease in yield. There is a point. Further, when the motor is miniaturized, the above-mentioned problems become larger and it is difficult to miniaturize the motor. In addition, even when the hall element 6 is outside the drive coil 5, there is a problem that the coil shape of the drive coil 5 can be limited and it is difficult to reduce the size.

The present invention has been made for the purpose of solving the problems of the prior art.

[Means for solving problems]

Means for solving the above problems will be described below with reference to FIG. 1 corresponding to the embodiment. According to the present invention, a rotor portion comprising a magnet 1 and a magnet yoke 2 which are polarized by N and S alternately in the circumferential direction, and a stator in which a printed circuit board 3 is fixed to an opposing surface facing the rotor portion. In a brushless motor composed of a yoke 4 and a stator portion composed of a drive coil 5 fixed to the printed circuit board 3 and a Hall element 6 for rotor position detection, a printed circuit board 11 is fixed to the opposite surface of the stator yoke 4. The Hall element 6 is arranged and connected to the printed circuit board 11 at a position corresponding to the inner space of the inner frame of the drive coil 5, and the through hole 12 is formed at the position corresponding to the Hall element 6 of the stator yoke 4. The Hall element 6 and the magnet 1 are directly opposed to each other via the interposition.

[Operation] In the device configured in this way, the Hall element 6
Is arranged and connected at a position different from the mounting surface of the driving coil 5, so that the short circuit between the terminals of the driving coil 5 and the terminals of the hall element 6 can be prevented, and the driving coil 5 is not affected by the hall element 6. The number of soldering lands is increased, and the flexibility of the coil shape and the number of coil turns of the drive coil 5 is increased.

〔Example〕

FIG. 1 is a diagram showing an embodiment of the present invention. In FIG. 1, 11 is a printed circuit board and 12 is a through hole. The printed circuit board 11 is fixed to the opposite surface of the stator yoke 4, that is, the back surface of the facing surface facing the rotor portion. The Hall element 6 is arranged and fixed on the printed circuit board 11 and is electrically connected. A through hole 12 is formed in the stator yoke 4 at a position corresponding to the Hall element 6. The magnetic flux of the magnet 1 is applied to the Hall element 6 through the through hole 12. FIG. 2 is a view of the present invention viewed from the tip side of the rotary shaft 8. Although not shown directly here, there is a through hole 12 at a position below the Hall element 6 in the drawing.

The Hall element 6 and the drive coil 5 are arranged and connected at different positions, respectively, so that the space elements are not bound to each other.

By fixing the printed circuit board 11 to the opposite surface of the stator yoke 4, it becomes possible to arrange and connect electronic components for driving the motor on the printed circuit board 11. As a result, the electronic components arranged in the radial direction of the rotary shaft 8 can be arranged in the axial direction of the rotary shaft 8 and the size can be reduced. Further, in the above embodiments, the Hall element 6 is arranged on the printed circuit board 11, but it may be embedded in the printed circuit board 11. As a result, the magnetic flux to the Hall element 6 increases.

〔The invention's effect〕

As described above, according to the present invention, the printed circuit board is fixed to the opposite surface of the stator yoke, and the hall element is arranged and connected to the printed circuit board at a position corresponding to the inner space of the inner frame of the drive coil. The hall element and the magnet are directly opposed to each other through a through hole formed at a position corresponding to the hall element of the stator yoke. Therefore, the soldering land can be increased, a short circuit between the drive coil terminal and the hall element terminal can be prevented, and the flexibility of the drive coil shape and the number of coil turns can be increased. Therefore, according to the present invention, it is possible to obtain the effects that the yield is improved and the size can be reduced.

[Brief description of drawings]

1 is a cross-sectional view showing an embodiment of the present invention, FIG. 2 is a view of a stator portion of the embodiment shown in FIG. 1 as seen from the tip end side of a rotary shaft, FIG. 3 is a cross-sectional view showing a conventional technique, FIG. 4 is a view of the conventional stator portion shown in FIG. 3 as seen from the rotor side. 1 …… magnet, 2 …… magnet yoke, 3 …… printed circuit board, 4 …… stator yoke, 5 …… drive coil, 6 …… Hall element, 11 …… printed circuit board, 12 …… through hole

Claims (2)

[Claims] 1. A rotor portion comprising magnets and magnet yokes, which are magnetized by N and S alternately in the circumferential direction, and a stator yoke having a printed circuit board fixed to an opposing surface facing the rotor portion. In a brushless motor composed of a drive coil arranged and connected to the printed circuit board and a stator section composed of Hall elements for rotor position detection, the printed circuit board is fixed to the opposite surface of the stator yoke, ， While placing and connecting the Hall element at the position corresponding to the inner space of the inner frame of the drive coil,
A brushless motor characterized in that the Hall element and the magnet are directly opposed to each other through a through hole formed at a position corresponding to the Hall element of the stator yoke. 2. The brushless motor according to claim 1, wherein electronic components for driving the motor are arranged and connected together with the Hall element on the printed circuit board.