JP2601049B2 - motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor used for various electronic devices.

[0002]

2. Description of the Related Art In recent years, motors have been heavily used in various electronic devices for the purpose of enhancing performance and increasing functions. In particular, a direct drive type motor has been adopted from early on in a rotary head device used for a video tape recorder or the like in order to minimize rotation unevenness.

Hereinafter, a motor in a conventional rotary head device will be described with reference to the drawings. FIG. 4 is a plan view of a magnet in the conventional example and the embodiment of the present invention, FIG. 5 is a side sectional view of a rotary head device equipped with a motor in the conventional example and the embodiment of the present invention, and FIG. FIG. 13 is a detailed view of a lead wire of a PG coil in a conventional example.

In FIG. 5, a shaft 13 is fixed to the center of a fixed drum 12. On the rotating drum 14,
At the center thereof, a hydrodynamic fluid bearing 15 which is rotatable with a predetermined gap from the shaft 13 is press-fitted and fixed. Thrust bearing 1
6 is slidably abutted on the tip of the shaft 13 and fastened to the rotating drum 14. Each of the rotary transformers 18a and 18b on the rotating side and the fixed side has a predetermined gap (about 50 to
70 μm) and is fixed to the rotating drum 14 and the fixed drum 12. The rotor unit 19 has an annular magnet 1 (FIG. 4) in which a plurality of first poles 2 (here, eight pairs, ie, 16 poles) are magnetized in the axial direction, and the rotor unit 19 is rotatably attached to the rotary drum 14. It is supported. The rotating yoke 20 made of a magnetic material is disposed to face the magnetized surface of the magnet 1 with a predetermined gap in the axial direction, is fixed to the rotor section 19, and can rotate integrally. As shown in FIG. 4, a second magnetic pole 3 for detecting a rotational phase, which will be described later, is formed at only one location on the outer periphery of the magnet 1.

Further, a stator 21 having an armature coil 4 to be described later is screwed to the fixed drum 12 in a gap defined by the rotating yoke 20 and the magnet 1. This stator portion 21 is provided on both sides of an insulating substrate 23 made of heat-resistant resin.
As shown in FIGS. 12A and 12B, the armature coils 4 formed by etching or plating are arranged at an equal pitch. Here, the armature coil 4 is 3
And 12 on each side of the stator section 21.
It is arranged individually.

Here, in order to detect the rotation speed of the motor, a frequency generator (Frequency-Genera) is used.
tor: FG) is generally required.
Here, as shown in FIG.
1 on the outer periphery of the armature coil 4 on the surface close to the magnet 1
The number of comb-shaped FG coils 10 in proportion to the number of the first magnetic poles 2 is arranged. This FG coil 10 has a magnet 1
Is rotated, a signal having a frequency proportional to the rotation speed of the magnet 1 is output.

In order to detect the rotational position of the motor, the rotary head device generates a position signal generator (Pulse-Generate) which generates an origin signal once per rotation of the motor.
or: abbreviated as PG). Here, as shown in FIG. 12 (B), the power generation wire element portion 31 is provided on the surface of the stator portion 21 close to the rotating yoke 20 at 360 / n.
A fan-shaped PG coil 9 having an opening angle of 45 degrees (here, 45 degrees) is provided.

The output waveform 24 of the PG coil 9 is shown in FIG.
As shown in (1), the leakage magnetic flux of the second magnetic pole 3 provided only at one place on the outer periphery of the magnet 1 is detected, and a positive and negative signal is generated once for each rotation, and the rotational phase of the rotary head 17 is detected. Used for The magnetic flux component generated for n cycles (8 cycles in this case) per rotation of the first magnetic pole 2 is because the power generation wire element 31 of the PG coil 9 has an opening angle corresponding to two poles of the first magnetic pole 2. Since the signals are canceled each other, they are not superimposed on the reproduction signal of the PG coil 9. FIG.
As shown in (B), the rotating yoke 20 on the stator portion 21
In order to avoid interference with the PG coil 9, the armature coil 4 on the side has one small coil shape for each phase, and the other coils are large. Further, a through hole 11 is provided for electrically connecting both surfaces of the insulating substrate 23 of the stator portion 21. Also, the suction plate 22
Is made of an annular magnetic material, is fixed to the stator section 21 via the holding member 26 coaxially with the rotor section 19 through a predetermined gap in the axial direction with the magnetized surface of the magnet 1, and The rotor portion 19 is urged toward the fixed drum 12 in the axial direction by magnetic attraction generated between them.

The operation of the rotary head device equipped with the conventional motor configured as described above will be described below.

First, when the energization of the armature coil 4 of a predetermined phase corresponding to the rotation phase of the magnet 1 is sequentially switched, the magnet 1 receives an attractive repulsive force and rotates in a predetermined direction. Magnet 1
Is rotated, the rotating drum 1 integrally fixed to the
4 also rotates. Here, the rotation speed of the rotary drum 14 is F
The output signal of the G coil 10 is controlled by a control circuit (not shown) so that the cycle of the output signal becomes a predetermined value. Also, the phase of the rotary head 17 is controlled based on the output signal of the PG coil 9 so as to record in synchronization with the vertical synchronizing signal of the video signal.

[0011]

However, in the conventional configuration, as shown in FIG. 13, the leading direction of the signal lead wire 32 of the PG coil 9 is not drawn in an arc direction coinciding with the center of the magnet 1. In addition, as the rotor section 19 rotates, the signal extraction line 32 generates power by itself due to the leakage magnetic flux of the first magnetic pole 2 provided on the magnet 1.
This causes a problem that the noise is superimposed on the output waveform of the PG coil 9 as a noise component, and the S / N ratio is deteriorated.

An object of the present invention is to solve the above-mentioned conventional problems and to provide a highly reliable motor with little PG noise.

[0013]

In order to achieve this object, a motor according to the present invention comprises an annular or cylindrical magnet in which 2n (n is a natural number) first magnetic poles are arranged at equal pitch intervals. at least one location is disposed on the first magnetic pole near
And different from the first magnetic pole closest to each other.
A second magnetic pole having a different polarity, a first power generating line element linking the leakage magnetic flux of the second magnetic pole, and a first power generating line linking the leakage magnetic flux of the second magnetic pole. 2π · m for the element
A PG coil disposed at a rotation phase shifted by / n (radian) (m is a natural number) and having a second power generation wire element electrically connected to the first power generation wire element; The first and second power generating wire elements are connected to the first and second power generating wire elements, respectively, and are configured with first and second lead wires. The first and second lead lines have an arc shape in which the center of the arc coincides with the center of the magnet.

[0014]

With the above construction, even if the leakage magnetic flux from the first magnetic pole interlinks the first and second lead wires during rotation of the magnet, it does not generate power by itself and generates a PG signal with less noise. can do.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of an armature of a motor according to the first embodiment. FIG. 2 is a detailed view of the lead wire of the PG coil in the first embodiment. FIG. 3 is an output waveform of the PG coil in the embodiment of the present invention. FIG.
Is a plan view of a magnet according to an embodiment of the present invention and a conventional example,
FIG. 5 is a side sectional view of a rotary head device equipped with a motor according to an embodiment of the present invention and a conventional example. In FIG.
A shaft 13 is fixed to the center of the fixed drum 12. At the center of the rotary drum 14, a dynamic pressure type fluid bearing 15 which is rotatable with a predetermined gap from the shaft 13 is press-fitted and fixed. The thrust bearing 16 is slidably abutted on the tip of the shaft 13 and fastened to the rotary drum 14. The rotary transformers 18a and 18b on the rotating side and the fixed side
Each is fixed to the rotating drum 14 and the fixed drum 12 with a predetermined gap (about 50 to 70 μm). Rotor part 1
9 is a plurality of poles in the axial direction (here, 8 pairs, ie, 16 poles).
An annular magnet 1 (see FIG. 4) magnetized with a first magnetic pole 2 (pole) is fixed and rotatably supported by a rotating drum 14. The rotating yoke 20 made of a magnetic material is disposed to face the magnetized surface of the magnet 1 with a predetermined gap in the axial direction, is fixed to the rotor section 19, and can rotate integrally. As shown in FIG. 4, a second magnetic pole 3 for detecting a rotational phase, which will be described later, is formed at only one location on the outer periphery of the magnet 1.

Further, a stator 21 having an armature coil 4 to be described later is screwed to the fixed drum 12 via a holding member 26 in a gap formed by the rotating yoke 20 and the magnet 1. As shown in FIGS. 1A and 1B, the stator portion 21 is formed by disposing armature coils 4 formed by etching or plating at equal pitches on both surfaces of an insulating substrate 23 made of a heat-resistant resin. I have. Here, the armature coils 4 are composed of three phases, and 12 armature coils 4 are provided on both surfaces of the insulating substrate 23.

Here, in order to detect the rotation speed of the motor, a frequency generator (Frequency-Genera) is used.
tor: FG) is generally required.
Here, as shown in FIG. 1A, the first magnet 1 is placed on the outer periphery of the armature coil 4 on the surface of the stator portion 21 close to the magnet 1.
Number of comb-shaped FG coils 10 in proportion to the number of magnetic poles 2
Is arranged. The FG coil 10 outputs a signal having a frequency proportional to the rotation speed of the magnet 1 when the magnet 1 rotates.

In order to detect the rotational position of the motor, the rotary head device generates a position signal generator (Pulse-Generate) which generates an origin signal once per rotation of the motor.
or: abbreviated as PG). Here, as shown in FIG. 4, near the first magnetic pole 2 of the magnet 1
A second magnetic pole 3 having a different polarity from the first magnetic pole 2 at only one location;
(In FIG. 4, the first magnetic pole 2 is an S pole, the second
The magnetic pole 3 is the north pole) . Further, as shown in FIG. 1B, a first power generation wire element portion 5 linked to the leakage magnetic flux of the second magnetic pole 3 and a second power generation wire portion 5 The first power generation wire element is linked to the leakage magnetic flux of the magnetic pole 3 and has an opening angle of 2π · m / n (radian) (45 degrees here) with respect to the first power generation wire element 5. A PG coil 9 having a second power generation wire element 6 electrically connected to the PG coil 9 is provided. Further, the first and second power generation wire element portions 5 and 6 have an arc shape, and the first and second lead wires 7 and 8 whose arc centers coincide with the center of the magnet 1 have through holes 11 formed therein. (See FIG. 2). The ends of the first and second lead wires 7 and 8 are connected to the terminal portions 30, respectively. The output waveform 24 of the PG coil 9 is shown in FIG.
As shown in (1), the leakage magnetic flux of the second magnetic pole 3 provided only at one place on the outer periphery of the magnet 1 is detected, and a positive and negative signal is generated once for each rotation, and the rotational phase of the rotary head 17 is detected. Used for For the magnetic flux component generated for n cycles per rotation of the first magnetic pole 2, the first power generation wire element 5 and the second power generation wire element 6 of the PG coil 9 are two poles of the first magnetic pole 2. Since they have a minute opening angle (45 degrees), they are canceled each other, so that they do not overlap with the output waveform 23 of the PG coil 9. Further, as shown in FIG. 1B, the armature coil 4 on the rotating yoke 20 side on the stator portion 21 is P
In order to avoid interference with the G coil 9, the shape of one coil in each phase is small, and the other coils are large. Further, the armature coils 4 on both surfaces of the insulating substrate 23 of the stator portion 21 are electrically connected by through holes (not shown). In addition, the suction plate 22
The stator 2 is made of an annular magnetic material and coaxial with the rotor 19 via a predetermined gap in the axial direction with the magnetized surface of the magnet 1.
The rotor portion 19 is urged toward the fixed drum 12 in the axial direction by magnetic attraction generated between the rotor portion 19 and the magnet 1.

The operation of the rotary head device equipped with the motor of the embodiment constructed as described above will be described below.

First, when the energization of the armature coil 4 of a predetermined phase corresponding to the rotation phase of the magnet 1 is sequentially switched, the magnet 1 receives an attractive repulsive force and rotates in a predetermined direction. Magnet 1
Is rotated, the rotating drum 1 integrally fixed to the
4 also rotates. Here, the rotation speed of the rotary drum 14 is F
The output signal of the G coil 10 is controlled by a control circuit (not shown) so that the cycle of the output signal becomes a predetermined value. Also, the phase of the rotary head 17 is controlled based on the output signal of the PG coil 9 so as to record in synchronization with the vertical synchronizing signal of the video signal. Further, as shown in FIG. 2, the output signal of the PG coil 9 has a first magnetic pole during rotation of the magnet 1 by forming the first and second lead wires 7, 8 into an arc shape matching the center of the magnet 1. 2, the first and second lead wires 7,
Even if the link 8 is linked, it does not generate power by itself and can generate a phase signal with little PG noise (FIG. 3).

As described above, according to the present embodiment, a highly reliable motor with little PG noise can be realized with a simple configuration.

In this embodiment, the first and second lead wires 7 and 8 are arc-shaped, but the through hole 11 and the terminal portion 30 are close to each other to prevent PG noise due to the shape of the lead wire. When the influence is small, the shapes of the lead lines 7 and 8 may be substantially straight.

In the embodiment of the present invention, the first and second
Lead wires 7 and 8 were arranged outside the PG coil 9,
It may be arranged inside the PG coil 9 (FIG. 6).

Further, in this embodiment, the armature coil 4 formed by plating or the like is disposed on both surfaces of the insulating substrate 23 in the stator portion 21. However, the present invention is not limited to this. Is wound on a bobbin, and the armature coil 4 formed into a fan shape is fixed on a fixed yoke 25 with an adhesive via an insulating layer (not shown). Further, the end face of the armature coil 4 and the magnet 1 are fixed to each other. PG, FG in the gap
A substrate 28 may be provided (FIG. 7). PG, FG
As shown in FIG. 8, a PG coil 9 and an FG coil 10 are provided on both sides of the substrate 28.

Further, in this embodiment, a surface-facing brushless motor is taken as an example, but a circumferential facing brushless motor as shown in FIG. 9 may be used. In FIG. 1, a magnet 1 has a cylindrical shape, and a first magnetic pole 2 is formed on an inner peripheral cylindrical surface thereof. The second magnetic pole 3 is formed on a PG / FG magnet 27 provided on the lower end surface of the magnet 1. The magnetization pattern of the PG and FG magnets 27 is shown in FIG.
0. The armature coil 4 has a core 29 formed by laminating silicon steel sheets punched by a press or the like.
It is wound around. PG coil 9, FG coil 10
Are fixed to the fixed drum 12. In the present embodiment, as shown in FIG.
The coil 10 has a PG coil 9 formed on the lower surface side. The first and second lead wires 7, 8 of the PG coil 9 have their arc centers coincident with the rotation centers as shown in FIG.
Therefore, also in this configuration, it is possible to improve the S / N ratio of the PG output.

Further, in the embodiment of the present invention, a so-called brushless motor in which a magnet rotates is taken as an example. However, the present invention is not limited to this, and a brush motor can be applied in exactly the same manner. It is obvious.

[0027]

As described above, according to the present invention, an annular or cylindrical magnet in which 2n (n is a natural number) first magnetic poles are arranged at equal pitch intervals, at least in the vicinity of the first magnetic pole. The first, which are arranged in one place and are closest to each other,
A second magnetic pole having a polarity different from that of the first magnetic pole, a first power-generating wire element linked to the leakage magnetic flux of the second magnetic pole, and a second magnetic pole linked to the leakage magnetic flux of the second magnetic pole; The second power line element is disposed at a rotation phase shifted by 2π · m / n (radian) (m is a natural number) with respect to the first power line element and electrically connected to the first power line element. A PG coil having a power generating wire element, and first and second PG coils respectively connected to the first and second power generating wire elements and disposed near the first and second power generating wire elements. And the first and second lead lines are formed in an arc shape having an arc center coinciding with the center of the magnet, so that leakage magnetic flux from the first magnetic pole during rotation of the magnet is provided. However, even if the first and second lead wires are linked, it is possible to eliminate its own power generation, generate a PG signal with less noise, and improve reliability. In which it can be realized had excellent motor.

[Brief description of the drawings]

FIG. 1 is a plan view of an armature of a motor according to a first embodiment of the present invention.

FIG. 2 is a detailed view of a lead wire of a PG coil according to the first embodiment of the present invention.

FIG. 3 is an output waveform diagram of a PG coil according to the embodiment of the present invention.

FIG. 4 is a plan view of a magnet according to an embodiment of the present invention and a conventional example.

FIG. 5 is a cross-sectional view of a rotary head device equipped with a motor according to the first embodiment of the present invention and a conventional example.

FIG. 6 is a plan view of an armature of a motor according to a second embodiment of the present invention.

FIG. 7 is a cross-sectional view of a rotary head device equipped with a motor according to a second embodiment of the present invention.

FIG. 8 is a plan view of a PG and FG substrate according to a second embodiment of the present invention.

FIG. 9 is a cross-sectional view of a rotary head device equipped with a motor according to a third embodiment of the present invention.

FIG. 10 is a magnetization pattern diagram of a PG and FG magnet according to a third embodiment of the present invention.

FIG. 11 is a plan view of a PG and FG substrate according to a third embodiment of the present invention.

FIG. 12 is a plan view of a motor armature in a conventional example.

FIG. 13 is a detailed view of a lead wire of a PG coil in a conventional example.

FIG. 14 is an output waveform diagram of a PG coil in a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Magnet 2 1st magnetic pole 3 2nd magnetic pole 4 Armature coil 5 1st power generation wire element 6 2nd power generation wire element 7 1st lead wire 8 2nd lead wire 9 PG coil 10 FG coil 11 Through hole

Claims (2)

(57) [Claims] 1. An annular or cylindrical magnet in which 2n (n is a natural number) first magnetic poles are arranged at equal pitch intervals, at least one magnet is arranged near the first magnetic pole , and
A second magnetic pole having a polarity different from that of the first magnetic pole closest to the first magnetic pole, a first power generation wire element linking the leakage magnetic flux of the second magnetic pole, and the second magnetic pole And the first magnetic flux
The second power generation unit is disposed at a rotation phase shifted by 2π · m / n (radian) (m is a natural number) with respect to the power generation line unit and electrically connected to the first power generation line unit. A PG coil having a wire element; and a first and a second coil connected to the first and second power generating wire elements and disposed near the first and second power generating wire elements, respectively. Motor with a lead wire. 2. The motor according to claim 1, wherein the first and second lead lines have an arc shape whose arc center coincides with the center of the magnet.