JPS6330208Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a brushless motor, and in particular, to prevention of warping of a substrate to which a stator coil is fixed.

Before explaining the present invention, first, the structure of a conventional brushless motor will be explained with reference to FIGS. 1 and 2. A magnetic disk 2 and another magnetic disk 3 are fitted onto the rotating shaft 1 at a predetermined interval, and an annular rotor is mounted on the surface of the disk 3 facing the disk 2. A magnet 4 is fixed concentrically to the shaft 1. A plurality of magnetic poles having alternately different polarities are formed on the end face of the magnet 4 in the direction of the axis 1.
A small-diameter disk 5 is also fitted onto the rotating shaft 1 and serves as a reinforcing material for the magnetic disk 3. A substrate 7 is located between the magnetic disc 2 and the rotor magnet 4. The substrate 7 is held by being held between the bent edges 8a and 9a of the open ends of the cases 8 and 9. The substrate 7, as also shown in FIG.
It has an inner hole 7a, through which the rotating shaft 1 passes with a sufficient distance. The substrate 7 has a protrusion 7b on its outer periphery in which a control circuit is to be incorporated.
is formed. A suitable number (four in the illustrated example) of stator coils 6 are fixed to the substrate 7. This stator coil 6 faces the rotor magnet 4 with a suitable distance between them. An electrical wiring pattern is printed on the opposite side of the substrate 7 to the surface to which the coil 6 is fixed, so that each of the coils and the circuit elements implanted in the protrusion 7b are electrically connected. It's summery. Rotating axis 1
is the bearing 1 fitted into the center holes of the cases 8 and 9.
It is rotatably supported by 0 and 11. In this example, the disks 2 and 3 form a magnetic circuit, and the cases 8 and 9 do not contribute to the formation of the magnetic circuit. this is,
This is in consideration of the case where the cases 8 and 9 are omitted and the case is directly incorporated into the chassis of various devices.

In the brushless motor configured in this way, when a rotating magnetic field is applied to the plurality of stator coils via the control circuit, the rotor magnet 4 is dragged by the rotating magnetic field, causing the rotor to rotate.

By the way, the board 7 itself may be warped, and the board 7 may be warped by immersing the printed pattern part in a solder bath and soldering the circuit elements after implanting the circuit elements. Those that have been rebellious from the beginning will become even more rebellious. When such a curved board 7 is incorporated into a brushless motor, the stator coil 6 fixed to the board 7 comes into contact with the rotor magnet 4.
Therefore, if the distance between the coil 6 and the magnet 4 is widened in order to prevent this, there will be a problem that the efficiency will deteriorate.

The present invention has been developed in view of the shortcomings of the prior art. By eliminating the bending of the substrate, the distance between the stator coil and rotor magnet can be kept small and stable, thereby increasing efficiency. It is an object of the present invention to provide a brushless motor in which contact between a stator coil and a rotor magnet can be eliminated.

Hereinafter, the present invention will be explained with reference to FIGS. 3 to 5.

In FIG. 3, the substrate 7 used in the present invention has one long groove 7c extending radially from the inner hole 7a.
is provided, and one of the plurality of stator coils 6 is placed and fixed across this long groove 7c.

According to the board for fixing the stator coil configured in this way, when the stator coil is fixed on the long groove 7c, the long groove 7c acts as a relief and absorbs the bending of the board 7, so that the board 7 is corrected to be flat. be done. Therefore,
If this is used as a board for a brushless motor as shown in FIG. 1, contact between the stator coil 6 and the rotor magnet 4 can be prevented, and the gap between the coil 6 and the magnet 4 can be narrowed. It is also possible to increase the efficiency of the motor.

One method of fixing each stator coil 6 to the substrate 7 is to press the coil 6, which is formed by winding and molding an electric wire coated with a fusion material, onto the long groove 7c of the substrate 7 while applying pressure, and then to attach the coil 6 to the substrate 7 using epoxy resin. There is a method of gluing and fixing. Further, as shown in FIG. 4, each stator coil 6 is formed using a winding core 12 made of a non-magnetic material such as resin, and wound with this winding core 12 crimped onto a substrate 7. The eyelet 13 may be inserted into the center hole 12a of the core 12, and the tip of the eyelet 13 may be further inserted into the attachment hole of the substrate 7 and fixed by caulking. When the stator coil 6 is fixed onto the long groove 7c of the substrate 7 as shown in FIG.
It may be inserted and caulked. In this way, when the coil 6 is fixed using the eyelet 13, the inner peripheral surface 6a of the coil 6 is tapered upward in FIG. 4, while the outer peripheral surface 12b of the core 12 is tapered. may also be formed into a similar tapered shape so that both surfaces are in contact with each other. In this way, the coil 6 is pressed against the outer circumferential surface 12b of the winding core 12, and the coil 6 is more firmly fixed to the substrate 7. In addition, when fixing the coil 6 to the substrate 7, both a method using an adhesive and a method using an eyelet may be used in combination.

The long grooves formed in the substrate 7 may be formed by cutting the substrate 7 from the outside toward the inside, as indicated by the reference numeral 7e in FIG. Further, the long grooves of the substrate 7 only need to be located at positions spanning at least one coil among the stator coils, and there may be a plurality of such long grooves. moreover,
Since the substrate 7 is held between the motor cases 8 and 9 (see Fig. 1), etc., the long grooves formed in the substrate 7 can be provided on the mutual surfaces of a plurality of stator coils to obtain a recoil correction effect. . Therefore, the long grooves formed under the stator coils 6 and those formed between the stator coils 6 may be used together. When the board 7 is clamped and fixed between the motor cases 8 and 9, the bent edges 8a and 9 of the cases 8 and 9
It may be tightened by a screw passing through a and the substrate 7, or it may be fixed by engaging bent pieces formed at the edges of the cases 8 and 9 with each other.

According to the present invention, it is possible to achieve the intended purpose as described above, and it is also possible to prevent the board from warping due to changes over time to some extent.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view showing an example of a conventional brushless motor, Fig. 2 is a perspective view showing the board of the same motor, Fig. 3 is an exploded perspective view showing an embodiment of the present invention, and Fig. 4 is a main body of the present invention. FIG. 5 is an exploded perspective view showing another embodiment of the invention. FIG. 5 is an exploded perspective view showing still another embodiment of the invention. DESCRIPTION OF SYMBOLS 1... Rotating shaft, 2, 3... Disk, 4... Rotor magnet, 6... Stator coil, 7... Substrate, 7c, 7e... Long groove, 7a... Inner hole.

Claims (1)

[Scope of utility model registration request] an annular rotor magnet that is integrally fixed to a rotating shaft and has a plurality of magnetic poles formed on an end face in the axial direction; and an inner hole in the center through which the rotating shaft is inserted; In a brushless motor, the brushless motor includes a substrate fixedly held on a machine frame opposite to the substrate, and a plurality of coils fixed to the substrate, the substrate having a long groove cut from an inner hole or an outer periphery, A brushless motor characterized in that the coil is fixed across the long groove.