JPH0632781Y2 - Brushless motor detector - Google Patents

Description

[Technical Field] The present invention relates to a motor provided in a drive unit of a compact disc player, a floppy disc player, a tape player, or the like, and more particularly to a motor for detecting the rotational speed and rotational position of a rotor. Detection device.

[Technical background and conventional technology]

FIG. 10 is a sectional view showing a part of a conventional brushless motor.

Reference numeral 1 is a rotor. The rotor 1 is fixed to a rotating shaft (not shown) rotatably supported on a fixed plate 2. The rotor 1 has a rotor yoke 3 and a drive magnet 4 fixed inside the lower surface thereof. A flexible coil substrate 5 is attached to the fixed plate 2, and a plurality of stator coils 6 are fixed on the coil substrate 5. The rotor 1 is rotationally driven by the electric current flowing through the stator coil 6 and the magnetic field of the drive motor 4.

An FG magnet 7 for detecting the rotation speed and a PG magnet 8 for detecting the rotational position are fixedly provided on the outer surface of the rotor yoke 3. The FG magnet 7 is magnetized such that the north pole and the south pole are alternately arranged at a short pitch in the rotation direction. Also PG
The magnets 8 are provided at one or two locations on the outer circumference of the rotor yoke 3.

The outer circumference of the rotor yoke 3 is surrounded by the fixed side plate 2a. The fixed side plate 2a is formed integrally with the fixed plate 2. A detection substrate 9 is attached to the inner surface of the fixed side plate 2a. The detection board 9 is formed of a flexible board. FIG. 11 shows the detection board 9 in a developed state. The detection board 9 has an FG pattern 11 for detecting the number of rotations.
And the PG pattern 12 for detecting the rotational position are printed. The FG pattern 11 is composed of a plurality of concavo-convex patterns corresponding to the arrangement pitch of the N and S magnetic poles of the FG magnet provided on the rotor yoke 3. The PG pattern 12 is formed in a convex shape at one location on the detection substrate 9.

When the rotor 1 rotates, the FG provided on the rotor yoke 3
The magnet 7 moves to face the FG pattern 11 on the detection substrate 9, and as a result, a pulse current is output from the FG pattern. Further, when the PG magnet 8 passes through the position facing the PG pattern 12 due to the rotation of the rotor 1, when the PG magnet 8 passes through this position,
One pulse current P shown in FIG. 8 is output from the PG pattern 12. The output pulse from the FG pattern 11 detects the rotational speed of the rotor 1, and the output pulse from the PG pattern 12 detects the rotational position of the rotor 1.

[Problems of conventional technology]

As shown in FIG. 11, in the conventional detection substrate 9, the FG lead pattern 11a for extracting the signal of the FG pattern 11 and the PG lead pattern 12a for extracting the signal of the PG pattern are provided on the output piece 9a of the detection substrate 9. , Are extended parallel to the same direction. Therefore, the PG lead pattern 12a becomes the FG pattern 11
Is passing through the same area (area indicated by 1) in which is formed. When the rotor 1 rotates, the FG magnet 7 passes through the area indicated by l, so that an electromotive force acts on the PG lead pattern 12a as the magnetic poles of the FG magnet 7 pass. As a result, as shown in FIG. 9, a fine noise pulse due to passage of the FG magnet 7 is output to the output current of the PG pattern 12. Detection of such a noise pulse causes various problems such as deterioration in accuracy of the rotational position detection operation by the PG pattern 12.

[Purpose of device]

The present invention has been made in view of the above-mentioned conventional problems, so that the PG lead pattern connected to the rotational position detection pattern of the detection board does not cross the passage area of the rotational speed detection FG magnet. And the PG for rotational position detection
An object of the present invention is to provide a motor detection device in which an output signal is accurately extracted.

[Means for Solving the Problems] In order to achieve the above object, the present invention is directed to a rotor which is rotationally driven, and an FG magnetizing portion for detecting a rotational speed and a PG magnetizing portion for detecting a rotational position which are adjacent to each other. Is provided, and a detection substrate is provided on the surface of the fixed portion facing the both magnetized portions facing the both magnetized portions. PG patterns are respectively formed at positions facing the PG magnetized portion, and the FG leads conducted to the FG pattern of the detection substrate are conducted in a direction not intersecting the PG magnetized portion and to the PG pattern. The PG leads extend in opposite directions so that they do not intersect the FG magnetized portion.
One of the lead and the FG lead is led out to the back side of the fixed portion with respect to the side where the detection substrate is provided.

[Operation] The operation of the present invention having the above configuration is that the FG lead formed on the detection substrate extends in the direction not intersecting the PG magnetized portion of the rotor, and the PG lead extends in the direction not intersecting the FG magnetized portion. As a result, noise due to the FG magnetizing part does not mix into the pulse signal for detecting the rotational position. Further, since the PG lead or the FG lead extends to the back side at the fixed portion, it becomes possible to extend the PG lead and the FG lead in the same direction for wiring processing.

[Example of device]

Embodiments of the present invention will be described below mainly with reference to the drawings of FIGS.

1 to 6 show a first embodiment of the present invention. FIG. 1 is a perspective view showing a mounting state of a motor detection board, FIG. 2 is a sectional view showing a part of a motor detection device, FIG. 3 is a development view of a detection board, and FIG. 4 is a whole motor. FIG. 5 is a sectional view showing the structure, FIG. 5 is a plan view showing the arrangement of stator coils of the motor, and FIG.

The motor shown in this embodiment is a brushless motor used as a power source for compact disc players, floppy disc players and tape players.
In this brushless motor, a rotary shaft 23 rotatably supported by a thrust bearing 21 and a radial bearing 22.
The rotor 30 is fixed to the. A rotor yoke 31 is fixed to the rotor 30, and a drive magnet 32 is fixed to the lower surface of the rotor yoke 31. Also, on the outer periphery of the rotor yoke 31, an FG magnet 33 for detecting the number of revolutions,
The PG magnet 34 for detecting the rotational position is fixed. As shown in FIG. 6, the driving magnet 32 has N poles and S poles alternately magnetized along the rotation direction thereof. The FG magnet 33 is fixed over the entire length of the outer circumference of the rotor yoke 31, and the N pole and the S pole of the FG magnet 33 are shorter than the magnetic pole of the driving magnet 32 along the rotation direction. It is magnetized at the pitch. Further, one or two PG magnets 34 are provided on the outer circumference of the rotor yoke 31.
Individually fixed.

A coil substrate 25 is fixed on the fixed plate 24, and a plurality of stator coils 26 are fixed on the upper surface thereof. An outer plate 24a is integrally provided on the peripheral edge of the fixed plate 24. The outer plate 24a has a tubular shape that surrounds the outer periphery of the rotor 30. The detection board 27 is attached to the inner surface of the outer plate 24a. As shown in FIGS. 1 and 3, the disk-shaped coil substrate 25 installed on the fixed plate 24 and the strip-shaped detection substrate 27 attached to the inner surface of the outer plate 24a are both flexible substrates. Both of the substrates 25 and 27 are integrally formed via the connecting piece 28. As shown in FIGS. 1 and 2, an output piece 25a is integrally formed in a strip shape from the edge of the coil substrate 25, and the output piece 25a is pulled out to the outside of the fixing plate 24. There is.

As shown in FIG. 5, a plurality of stator coils 26 are installed on the coil board 25, and each stator coil 26 is connected to a lead pattern on the coil board 25. Then, current is supplied to each stator coil 26 via the lead pattern on the output piece 25a and the lead pattern on the coil substrate 25.

Further, as shown in FIG. 3, an FG pattern 41 for detecting the rotational speed and a PG pattern 42 for detecting the rotational position of the rotor 30 are printed on the detection substrate 27. The FG pattern 41 is composed of a plurality of concave-convex patterns and faces the FG magnet 33. The PG pattern 42 is composed of one convex pattern and faces the passage portion of the PG magnet 34. FG lead pattern 41a from both ends of FG pattern 41
However, the PG lead patterns 42a extend from both ends of the PG pattern 42, and the lead patterns 41a and 42a extend in directions opposite to each other. That is, as shown in FIG. 3, the FG lead pattern 41a extends from the connecting piece 28 to the coil board 25, and the pattern on the coil board 25 causes the lead pattern of the stator coil 26 and the output piece 25a to reach the outside. Have been drawn to. Further, the PG lead pattern 42a is extended to the detour piece 27a extended from the upper end of the detection substrate 27. And this detour piece 27a
Is a coil board 2 that bypasses the outer peripheral surface from the upper end of the outer plate 24a.
It merges with the output piece 25a of 5 (see FIG. 2), and the PG lead pattern 42a is soldered to the lead pattern on the output piece 25a.

Next, the operation will be described.

A current is alternately applied to each coil 26 clockwise and counterclockwise. That is, the hall element or the like detects the polarity of the driving magnet 32 located above it, and accordingly the current flows in each of the coils 26 in the left and right directions. An electromagnetic force in the rotational direction is exerted by the current flowing through the side end portion 26a (see FIG. 5) of the coil 26 and the magnetic field formed by the driving magnet 32, and the rotor 30 and the rotary shaft 23 are rotationally driven. .

During this rotation operation, the FG pattern 41 on the detection substrate 27,
A continuous pulse current flows according to the movement of the polarity of the FG magnet 33 fixed to the outer periphery of the rotor yoke 31. This current is guided by each FG lead pattern 41a and is drawn to the outside through the coil substrate 25 and the lead pattern on the output piece 25a. The number of rotations of the motor can be detected by counting this continuous output pulse. In a compact disc player, a floppy disc player, or the like, the current supplied to the coil 26 is controlled according to the detected number of rotations, and the rotation speed of the disc drive unit is controlled. Further, the PG pattern 42 of the detection substrate 27,
When the PG magnet 34 passes, a current corresponding to its polarity flows. This current is guided by the PG lead pattern 42a, but this current passes along the detour piece 27a, passes through the upper end and the outside of the outer plate 24a, and is drawn to the outside from the lead pattern on the output piece 25a. The eighth from the PG pattern 42
The pulse P shown in the figure is output. The output pulse detects the rotational position of the rotor 30, and in the case of a disc player, the read or write start timing is set.

Here, unlike the conventional one, in the present invention, the PG pattern
The PG lead pattern 42a connected to 42 is the detour piece 27a.
Since it is diverted to the outside of the outer plate 24a, the PG lead pattern 42a does not cross the passage area of the FG magnet 33. Therefore, when the rotor 30 rotates, the output from the PG pattern 42 is not affected by noise from the FG magnet 33, and a pure PG output pulse P as shown in FIG. 8 is obtained. On the contrary, since the FG lead pattern 41a connected to the FG pattern 41 is out of the passage area of the PG magnet 34, the FG output pulse is
It is no longer affected by the magnetic poles.

FIG. 7 shows a second embodiment of the present invention.

This embodiment shows the detection substrate 50 in the case where the FG magnet 33 and the PG magnet 34 are arranged in a plane on the lower surface of the rotor yoke 31 together with the driving magnet 32. In this case, the FG pattern 41 and the PG pattern 42 are arranged in a plane with respect to the disc-shaped detection substrate 50. FG lead pattern 41a connected to FG pattern 41 and PG pattern 4
The PG lead patterns 42a connected to 2 extend in opposite directions. Then, the PG lead pattern 42a is fixed to the fixing plate 5
The PG lead pattern 42a is prevented from being affected by the FG magnet by such a structure as to detour to the lower side of 1.

In the illustrated embodiment, the drive magnet 32, the FG magnet 33, and the PG magnet 34 are composed of different magnets, but these magnets may be integrated.

Furthermore, the same applies to the arrangement of the FG magnet 33 and the PG magnet 34, and the arrangement of the FG pattern 41 and the PG pattern 42, which are upside down from those of the illustrated embodiment.

Further, the FG lead and the PG lead may be configured by lead wires instead of the pattern on the substrate.

[Effect of device]

As described above, according to the present invention, the lead for the rotational position detection pattern and the lead for the rotational speed detection pattern extend in opposite directions, so that both leads pass through the pass region of each magnetized portion. You will not cross. Therefore, each lead is not affected by the magnetized portion for other uses, noise due to detection of the other magnetized portion is not generated, and highly accurate rotational position detection or rotational speed detection can be performed. Further, since either one of the PG lead and the FG lead is led out to the back surface side of the fixed portion, it is possible to wire both leads in the same direction.

[Brief description of drawings]

FIG. 1 is a perspective view showing a mounting portion of a detection board of a motor detection device according to a first embodiment of the present invention, FIG. 2 is a sectional view showing a part of a motor detection device, and FIG. Development view,
FIG. 4 is a sectional view showing the entire structure of the motor, FIG. 5 is a plan view showing the arrangement of the stator coils, FIG. 6 is a plan view showing the facing relationship between the stator coils and the drive magnets, and FIG.
FIG. 8 is a plan view showing a detection substrate of a motor detection device according to a second embodiment of the present invention, FIG. 8 is an explanatory view showing rotational position detection pulses by the detection device of the present invention, and FIG. 9 is a conventional detection device. FIG. 10 is an explanatory view showing a rotational position detection pulse, FIG. 10 is a sectional view showing a part of a conventional motor detection device, and FIG. 11 is a development view of a conventional detection substrate. 23 …… Rotary axis, 24 …… Fixed plate, 24a …… Outside plate, 25 ……
Coil board, 26 …… stator coil, 27,50 …… Detection board, 30 …… Rotor, 31 …… Rotor yoke, 32 …… Drive magnet, 33 …… FG magnet, 34 …… PG magnet, 41 …… FG Pattern, 41a …… FG lead pattern, 42
…… PG pattern, 42a …… PG lead pattern.

Claims (1)

[Scope of utility model registration request] 1. A rotatably driven rotor is provided with an FG magnetizing portion for detecting the number of revolutions and a PG magnetizing portion for detecting a rotational position, which are adjacent to each other, and fixed so as to be opposed to both magnetized portions. A detection substrate is provided on the surface of the detection unit facing the both magnetized portions, and an FG pattern is provided at a position facing the FG magnetized portion of the detection substrate, and a PG pattern is provided at a position facing the PG magnetized portion. The FG leads formed respectively in the FG pattern of the detection substrate are in directions opposite to each other in a direction not intersecting with the PG magnetized portion, and in the direction in which the PG leads conducted to the PG pattern are not intersected with the FG magnetized portion. A brushless motor detection device that is extended and one of the PG lead and the FG lead is led out to the back side of the fixed portion with respect to the side where the detection substrate is provided.