JPS6260457A - Flat type motor - Google Patents

Abstract

PURPOSE:To scale down the size of a motor by forming radial slits at the central section of a magnetic pole for a surface facing type rotor magnet and mounting a coil having the same shape as said slits onto a printed substrate. CONSTITUTION:A flat type motor is constituted of a rotor magnet 14, a rotor yoke 2, a shaft 4, a stator coil 5, a printed substrate 9 fitted between the rotor magnet 14 and the stator coil 5, etc. In this case, a slit 15 is shaped at the central section of one magnetic pole of the rotor magnet 14, and a coil-shaped pattern having the same width W and length L as the slit 15 is also formed to the printed substrate 9. Accordingly, one rotational pulse can be acquired per revolution in the coil pattern, thus also scaling down the size of the titled motor.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a flat type electric motor having a rotor magnet and a stator coil that are opposed to each other in a plane, and is equipped with one rotating pulse generator per revolution. .

BACKGROUND OF THE INVENTION In recent years, portable type devices such as tape recorders and VTRs have come into widespread use, and flat electric motors are often used as drive sources for these devices.

With the miniaturization of these devices, there is a strong desire for flat electric motors to be lighter, thinner, and smaller.

In this case, the configuration of the rotational pulse generator is often significantly related to the motor dimensions and cost.

An example of the conventional flat type electric motor mentioned above will be described below with reference to the drawings.

FIG. 2 shows a cross section of a conventional flat type electric motor.

In Figure 2, 1 is a rotor magnet, 2 is a rotor yoke,
3 is a rotor boss, 4 is a shaft, 5 is a stator coil formed of self-fused electric wire or the like to match the shape of a magnet of the rotor magnet 1 fixed at a position facing the rotor magnet 1, e is a stator yoke, and 7 is a stator coil. A phase switching sensor such as a Hall element, 8 is a bearing. Further, 9 is a rotor magnet 1 and a stator coil 6.
A printed circuit board 9 is located between the stator coils and is attached to the stator coil.
10 is a small magnet for generating one rotational pulse per rotation, and one piece is pasted on the outer circumference of the rotor yoke 2. It is being

11 is a Hall element for detecting the magnetic flux of this small magnet, and is soldered on the board 9.
A Hall voltage is generated every time 0 comes to a position facing the Hall element 11. By amplifying this Hall voltage, 1
One rotation pulse is obtained per rotation. This one signal per rotation is used as an origin signal per rotation of the rotor, and supplies a signal necessary as an index signal in, for example, a floppy disk drive.

In order to drive the motor, a drive circuit is required in addition to this, but it is not directly related to the present invention and will therefore be omitted.

FIG. 3 shows another conventional example. In the same figure, 2 to 6 and 9 are the same components as in the first conventional example shown in FIG. 2, so their explanation will be omitted. Reference numeral 12 denotes a reflective plate attached to one location on the outer periphery of the rotor yoke 2, and is made of a shiny metal piece.

Reference numeral 13 denotes a rotating pulse generation sensor in which a light emitting photodiode and a light receiving phototransistor are integrally formed.
The reflected light from the photodiode is detected by a phototransistor and converted into an electrical signal.

Problems to be Solved by the Invention However, in the above configuration, in order to obtain one rotational pulse per rotation, it is necessary to use a small magnet or a reflector for generating rotational pulses, or a Hall element for detecting rotational pulses. A sensor called a phototransistor is required.
The number of parts increases, making it expensive, and in terms of dimensions (6 sensors, etc. are attached to the outer circumference of the motor), the required external dimensions of the motor are increased.

Means for Solving the Problems In order to solve the above problems, the flat type electric motor of the present invention has a radial slit provided in the center of one magnetic pole of the surface-facing rotor magnet, and a radial slit between the rotor magnet and the stator coil. A radially arranged coil having the same width and length as the slit on the rotor magnet is formed on a printed circuit board provided between the rotor magnets.

Operation The present invention attempts to obtain 91 rotation pulses per revolution by using the above-described configuration without increasing the number of parts of the motor or the external dimensions of the motor.

EXAMPLE Hereinafter, a flat electric motor according to an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a sectional view of a flat electric motor according to an embodiment of the present invention. In FIG. 1, 2 to 8 are the same components as in the conventional example shown in FIG. 2, so their explanation will be omitted. 14 is a rotor magnet, and the difference from the conventional example shown in FIG. 2 is that the rotor magnet 14 has a slit in the center of one magnetic pole. Figure 4 shows a sketch of the rotor magnet. Although the figure shows a case where the rotor magnet is magnetized with eight poles, the present invention is not concerned with the number of poles. One slit 15 in FIG. 4 is provided radially at the center of one magnetic pole, and the slit width and length are W and L, respectively.

Reference numeral 16 in FIG. 1 is a component having the same structure as the printed circuit board 9 in the conventional example shown in FIGS. 2 and 3, but the difference from the conventional example is that the slit 1 of the rotor magnet 14
It has a coil-shaped pattern 17 having the same width (b) and length direction as 6. Figure 5 shows the printed circuit board 16.
The coiled pattern 17 above is shown. One coil pattern is formed radially at a position that can face the slit 15 of the rotor magnet 14. This printed circuit board 16 is formed with soldering patterns for the Hall element T and the stator coil 5, as in the conventional example shown in FIG.
Since it has no direct relation to the present invention, illustration and description will be omitted.

In the flat electric motor configured as described above, the sixth
The operation will be explained using figures.

FIG. 6(a) shows the printed circuit board 16 when the motor shown in FIG. 1 is constructed using the 8-pole magnetized rotor magnet shown in FIG. 4, and the rotor rotates once at a constant speed. It shows how the magnetic east density Bq changes at the position of the upper coil pattern 17. The reason why the magnetic flux density suddenly decreases at time t8 is because the slit 15 of the rotor magnet 14 has come to the position of the coil pattern 17 on the printed circuit board 16.

FIG. 6(b) is the same as the change in magnetic flux density Bq in the negative (-) diagram of the magnetic flux interlinking with the coil pattern 17. Figure 6 (
C) is a coil on the printed circuit board 16 shown in FIG. 5, so near time t, as shown in FIG. voltage is generated. This peak value ep1 is t8
This value is larger than the peak value ep2 other than the nearby peak value ep2. Here, when the intermediate value es between epl and ep2 is input to the comparator level tositter comparator circuit with the induced voltage waveform shown in FIG. 6(C), the output waveform e0 becomes as shown in FIG. 6(d). As a result, it is possible to obtain rotational pulses per revolution.

Effects of the Invention As described above, the present invention provides a radial slit in the center of one magnetic pole of a surface-facing rotor magnet, and a printed circuit board provided between the rotor magnet and the stator coil. By forming one radially arranged coil with the same width and length as the slit, there is no need for parts to obtain one rotational pulse per rotation as in the conventional example.
Moreover, for this reason, the dimensions of the motor can also be made smaller than in the conventional example, which has a very large industrial advantage.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a shoji-type electric motor according to an embodiment of the present invention, FIG. 2 is a cross-sectional view of a conventional flat-type electric motor, FIG. 3 is a perspective view of another conventional flat-type electric motor, and FIG. 6 is a perspective view of a rotor magnet according to an embodiment of the present invention, and FIG. 6 is a diagram of a coil pattern of a printed circuit board according to the same embodiment.
T-沁. 2...Rotor yoke, 4...Shaft, 6...Stator coil, 6...Stator yoke, 14...Rotor magnet, 16...・・・
... Slit on the rotor magnet, 16 ... Printed circuit board, 17 ... Coil pattern on the printed circuit board. Name of agent: Patent attorney Toshio Nakao and 1 other person2-
-Rotor 3-ri f4--1 Rok Hajishi tS--Slit Fig. 2 Fig. 3 Fig. 4 Fig. 8I5 Fig. 6

Claims (1)

[Claims] In a flat electric motor, the rotor magnet includes a rotor magnet, a stator coil fixed at a position facing the rotor magnet, and a printed circuit board located between the rotor magnet and the stator coil and provided on the stator coil. One magnetic pole has a radial slit in the center, and a pattern on the printed circuit board that forms one coil having a shape equal to the width and length of the slit and arranged radially. A flat electric motor characterized by: