JPH0847231A - Motor - Google Patents

Abstract

PURPOSE:To provide a motor wherein highly accurate FG signals can be obtained and sufficient torque characteristic be also obtained regardless of magnetic material with low energy product. CONSTITUTION:An FG magnetic pole boundary 9a and a magnetic pole boundary 8a for driving are shifted each other by a half of one pole of 22.5 deg. in opening angle of an FG magnetic pole, that is, 11.25 deg., in such a way that they will not become in the same phase. A PG electric pole 10 is formed on one S pole of electric poles 8 for driving. A pair of FG output terminals 3 are prepared on the outer periphery side of a stator substrate 7. Further, a pair of FG leading wire-element pairs 2 are prepared to relay between an FG output terminal 3 and FG coil 1. The pairs 2 are formed by two conductive patterns that are close to each other. In a phase where an FG power generation wire-element 5 is aligned with the boundary 9a and an FG output becomes zero, a straight line connecting the center of a PG magnetic pole 10 with a rotational center and the pair 2 are set in a manner to become in the same phase.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor equipped with a frequency generator (hereinafter abbreviated as FG) most suitable for a rotary head drum motor or a capstan motor of a VTR.

[0002]

2. Description of the Related Art F as a rotor rotation frequency detecting means
The motor equipped with G is a video tape recorder (hereinafter referred to as V
Abbreviated as TR. ) Is widely used for driving capstans, rotary head drums, etc., and there is a strong demand for lower cost and higher performance. Further, along with the need for smaller and lighter equipment, higher efficiency of the motor is also required.

As an FG which is smaller and lighter than the conventional one and has relatively high detection accuracy of the rotational angular velocity, an annular FG is used.
A magnet is multi-polarized on one plane and fixed to the rotor, and a zigzag comb tooth coil is arranged on the stator side so as to face the magnetic pole surface of the FG magnet with a certain gap. The full-circumferential integral type FG is well known and is used in a drive motor of a rotary head drum of a VTR or the like.

An FG used in a conventional rotary head drum motor will be described below with reference to the drawings.

FIG. 18 is a cross-sectional view of a rotary head drum having a conventional structure in which a motor is incorporated.
The shaft 12 having a mirror-finished outer periphery and end face is the fixed drum 1.
5 is shrink-fitted and fixed. On the other hand, at the center of the rotary drum 14, a plurality of precision-processed wedge-shaped dynamic pressure generating grooves (not shown) are provided. Furthermore, the rotating drum 1
A thrust receiving member 16 is arranged so as to close the central through hole of No. 4. Here, lubricating oil is drip-drained between the shaft 12 and the rotary drum 14 and the thrust receiving member 16, and when the rotary drum 14 rotates in a predetermined direction, dynamic pressure is generated to operate as a fluid bearing. Rotate the rotor without contact.

A plurality of video heads (not shown) are arranged on the rotary drum 14. Here, the tape-shaped medium (not shown) is a fixed drum 15 and a rotating drum 14.
And a video track is formed obliquely on the tape medium by the rotation of the video head and the transport of the tape medium. Signals are exchanged between the video head and a recording / reproducing circuit (not shown) through the rotary transformer 17.

The rotor magnet 6 is integrally fixed to the rotary drum 14 via the rotor yoke 13.
As shown in FIG. 17, the rotor magnet 6 is provided with driving magnetic poles 8 in a fan shape at equal pitches. Drive magnetic pole 8
In this example, 16 poles are magnetized corresponding to the number of radially extending portions of the FG coil 1 described later. When the drive magnetic pole 8 is magnetized, the accuracy is controlled so that the center of magnetization of the drive magnetic pole 8 coincides with the center of rotation. Further, one pole (S pole in this example) of the driving magnetic poles 8 is provided with a PG magnetic pole 10 whose polarity is reversed.

The stator substrate 7 is fixed to the fixed drum 15 with screws (not shown). A main coil 18 that generates a rotational biasing force between the stator base plate 7 and the rotor magnet 6 by applying a predetermined electric current to the stator base plate 7.
And the fixed yoke 1 for forming the magnetic path of the rotor magnet 6.
9 and 9 are fixed.

On one plane of the stator substrate 7, FIG.
As shown in FIG. 4, a comb-tooth-shaped FG coil 1, FG lead-out wire element pair 2, and FG output terminal 3 having 16 FG power generation wire elements 5 are arranged by etching or the like. The start end and the end of the FG coil 1 are electrically connected to the FG output terminal 3 via the FG lead wire element pair 2. Further, twelve wedge-shaped main coils 18 are arranged on the stator substrate 7 in order to perform three-phase full-wave drive.

The PG magnetic pole 10 generates a signal for each rotation of the rotor by a PG coil (not shown) provided for a so-called PG signal for detecting the rotation phase of the rotary drum 14.

The operation of the above configuration will be described. The magnetic flux of the drive magnetic pole 8 of the rotor magnet 6 is linked to the FG coil 1 arranged on the stator substrate 7. Here, the rotor magnet 6
When rotationally driven in a predetermined direction by the rotational biasing force generated between the main coil 18 and the main coil 18, the magnetic flux interlinking with the FG coil 1 changes due to the rotation, so that the FG coil 1 has the rotor magnet 6 A rotation frequency signal (hereinafter abbreviated as FG signal) having a frequency proportional to the rotation speed is generated. In this embodiment, a sinusoidal signal having 8 pulses per rotation can be obtained. FIG. 9 shows an FG signal waveform in the ideal state in which no noise is superimposed at this time.

This FG signal is input to a drive control circuit (not shown) of the motor to control the rotation of the motor so that the cycle T when the FG signal becomes 0 becomes a predetermined value.

Here, when the noise component indicated by the broken line is superimposed on the FG signal as illustrated by the solid line in FIG. 14, FIG. 15 and FIG. 16, the period T at which the FG signal crosses 0 is shown. It causes an error. Here, the main cause of the noise component is the leakage magnetic flux component of the drive magnetic pole 8 and the PG magnetic pole 1.
There is zero leakage flux component. In addition, the noise components are generated in the FG coil 1 itself, the lead wire element portion from the FG coil 1, and the like.

When such a noise component is included, the motor drive circuit tries to apply control based on the incorrect information, and as a result, the motor causes uneven rotation. Become. Therefore, at the phase where the FG signal crosses 0, noise components that disturb the cycle must not be superimposed.

In the conventional example shown here, the driving magnetic pole 8 is magnetized to 16 poles and does not contribute to the noise of the FG output, so that the PG magnetic pole 10 may possibly contribute to the noise component. It is a leakage magnetic flux component.

In this conventional example, the magnetizing phase of the PG magnetic pole 10 is strictly controlled, and the size of the PG magnetizing yoke (not shown) is set so that the size of the PG magnetic pole 10 does not become large. Therefore, when the output signal of the FG coil 1 crosses 0, the leakage magnetic flux of the PG magnetic pole 10 is
The FG signal waveform of is not disturbed. In addition, the FG lead wire element pair 2 is separated from the PG magnetic pole 10 and
Since the magnetic flux density of the leakage magnetic flux from the magnetic pole 10 is relatively small, the leakage magnetic flux of the PG magnetic pole 10 does not superpose a noise component in the FG extraction line element pair 2.

[0017]

However, the above conventional example has the following problems. In the conventional example, the leakage magnetic flux of the driving magnetic pole 8 is directly used as the interlinkage magnetic flux to the FG coil 1, so that it is magnetized to 16 poles. However, in order to magnetize the rotor magnet 6 with 16 poles and perform three-phase full-wave drive, generally 12 main coils 18 are required, and there is a problem that the number of parts and the number of assembling steps increase.

If the number of magnetic poles is increased in this way,
Since the absolute value of the leakage magnetic flux from the driving magnetic pole 8 decreases,
The electromagnetic conversion efficiency of the motor deteriorates, resulting in increased power consumption and required motor characteristics (torque-rotation speed characteristics, etc.)
There is a problem that it is difficult to obtain.

Therefore, in order to alleviate the reduction in electromagnetic conversion efficiency and obtain the required motor characteristics, it is necessary to use a magnet made of a material having a high energy product. Therefore, a magnet made of a material having a low energy product such as a ferrite magnet cannot be used, and a rare earth magnet material having a high cost such as a samarium-cobalt-based or neodymium-iron-based magnet has to be adopted. This has a problem of increasing the cost of parts.

When a magnet having such a high energy product is used in a motor, it is necessary to increase the thickness of the rotor yoke 13 and the fixed yoke 19 in order to avoid magnetic saturation. Worsens, leading to higher cost of parts.

Further, for magnetizing a magnet having a high energy product, generally, a material of the magnetizing yoke is also a material having a high magnetic permeability and a high saturation magnetic flux density, and a magnetizing power source requires a device having a large capacity. Therefore, the cost will be increased in terms of production equipment.

Here, in order to increase the level of the leakage magnetic flux component from the drive magnetic pole 8 without increasing the energy product of the magnet material, it is conceivable to reduce the number of magnetic poles attached to the drive magnetic pole 8. As an example thereof, as shown in FIG. 19, an FG magnetic pole 9 is provided on the outer peripheral side, which is multi-pole magnetized with 16 poles.
It is conceivable to provide a driving magnetic pole 8 that is multi-pole magnetized with eight poles on the inner peripheral side. In this case, the shape of the FG coil 1 is set so as to interlink with the leakage magnetic flux of the FG magnetic pole 9.
Incidentally, the PG magnetic pole 1 provided on one S pole of the FG magnetic pole 9
The size of the magnetic pole of 0 is larger than that in the case of using a rare earth magnet material such as a neodymium iron magnet material. This is because when the magnet material is a ferrite-based material having a low energy product, the magnetic flux density of the leakage magnetic flux of the PG magnetic pole 10 becomes small, and a sufficient PG output cannot be obtained.

However, in the case of such a configuration,
The following new challenges arise. The area per pole of the driving magnetic pole 8 becomes larger than that of the conventional one, and the leakage magnetic flux of the driving magnetic pole 8 becomes wider than that of the conventional one. As a result, the leakage magnetic flux of the drive magnetic pole 8 reaches the FG extraction line element pair 2 and is superimposed on the FG output as a noise component. In this example, the driving magnetic poles 8 are multi-polarized to 8 poles, so that in the FG lead-out wire element pair 2, noise of 4 cycles per rotation is superimposed as shown by the broken line in FIG. Become. This noise component is F at the driving magnetic pole boundary 8a.
The noise level is maximized when the rotational phase matches the G leader line element pair 2. When the output waveform of the FG coil 1 crosses zero at the rotation phase where the noise level is maximum, the cycle T of the FG output is greatly disturbed.

Further, the center of magnetization of the drive magnetic pole 8, the center of the FG coil 1 and the center of rotation coincide with each other, the magnetic pole strength unevenness for each magnetic pole is 0, and the FG coil 1 is free from surface wobbling. In the ideal state, even if noise is superimposed on the FG power generation line element 5 due to the leakage magnetic flux of the driving magnetic pole 8, the noise components are canceled by the omnidirectional integration effect arranged over the entire circumference. However, when the magnetization center is displaced from the rotation center and there is surface wobbling of the FG coil 1,
When the strength of each magnetic pole is uneven and the FG coil 1 is misaligned, the leakage magnetic flux component of the driving magnetic pole 8 superimposed on the FG power generating line element 5 remains without being completely canceled. For example, when the driving magnetic poles 8 have different magnetization pitches at only one location and the FG coil 1 causes surface wobbling, the noise component has a pulse shape of eight times per rotation as shown by the broken line in FIG. In such a case, the cycle T of the FG output waveform will be greatly disturbed.

In order to eliminate the influence of noise components on the FG waveform in such a structure, the assembly accuracy such as the unevenness of the magnetization pitch of the driving magnetic pole 8 is strictly controlled, and the outer diameter of the driving magnetic pole 8 is controlled. It becomes necessary to take it small. As a result, the assembly cost of the motor increases, it becomes impossible to satisfy the torque characteristics required by the motor, and the electromagnetic conversion efficiency also decreases.

Further, since the ferrite magnet material is used, a small PG as when using a rare earth magnet is used.
Since the PG magnetic pole 10 cannot obtain a sufficient PG output, the size of the magnetic pole of the PG magnetic pole 10 is increased. Therefore, the leakage magnetic flux of the PG magnetic pole 10 becomes wider than that when a rare earth magnet material is used. As a result, FG
The leakage magnetic flux of the PG magnetic pole 10 interlinks with the lead wire element pair 2, and a noise component as shown in FIG. 16 is generated, which changes the FG cycle T.

Further, even if the relative magnetization phase of the PG magnetic pole 10 to the FG magnetic pole 9 is slightly deviated, P is applied to the FG power generation line element 5 in the rotation phase where the FG output waveform crosses 0.
The leakage flux of the G magnetic pole 10 will be linked,
There is a problem that a noise component is generated. In this conventional example, it is necessary to magnetize the PG magnetic pole 10 after magnetizing the FG magnetic pole 9, and at this time, a relative phase shift occurs. As a result, the FG cycle T fluctuates greatly, and the variation in the level becomes extremely large, so that the variation in the performance of the device also increases.

Here, in order to improve the torque characteristics, it is necessary to increase the outer diameter of the driving magnetic pole 8. As an example, as shown in FIG. 20, the FG magnetic pole 9 is connected to the rotor magnet 6
It is conceivable that the FG coil 1 is arranged on the inner peripheral side and the FG coil 1 is also arranged on the inner peripheral side. Here, the inner diameter of the drive magnetic pole 8 is set large so that the leakage magnetic flux of the drive magnetic pole 8 does not interlink with the FG power generation line element 5. As a result, the magnetic flux linkage to the main coil 18 is slightly reduced, but the torque characteristic is not deteriorated as compared with the case where the FG magnetic pole 9 is arranged on the outer peripheral side of the drive magnetic pole 8 as in the second conventional example. Relatively few.

However, in this configuration, since the FG lead-out wire element pair 2 interlinks with the driving magnetic pole 8, a problem occurs that noise due to the leakage magnetic flux is superimposed on the FG output. As a result, the FG cycle is disturbed, and the motor causes uneven rotation.

In view of the above problems, an object of the present invention is to satisfy the motor characteristics without using an expensive rare earth magnet material, suppress the influence of superposed noise on the FG signal period, and obtain a highly accurate FG signal. That is.

[0031]

Means for Solving the Problems A first method for solving the above problems is described below.
According to the technical means of the invention, when the FG power generation line element and the FG magnetic pole boundary are in the same phase and the FG output voltage becomes 0, F
The G power line element and the magnetic pole boundary of the driving magnetic pole were set so as not to have the same phase.

The technical means of the second invention for solving the above-mentioned problem is to arrange the FG power generation line element and the FG magnetic pole in close proximity to each other when the magnetic pole boundary is in the same phase and the FG output voltage is 0. The pair of FG lead wire pairs and the magnetic pole boundary of the driving magnetic pole were set so as not to be in the same phase.

The technical means of the third invention for solving the above-mentioned problems is to rotate the PG magnetic pole center and the PG magnetic pole when the FG power generation line element and the FG magnetic pole have the same magnetic pole boundary and the FG output voltage becomes zero. The straight line connecting the center and the FG power generation line element were set to have the same phase.

The technical means of the fourth invention for solving the above-mentioned problems is to rotate the FG magnetic pole center and the PG magnetic pole when the magnetic pole boundary between the FG power generation line element and the FG magnetic pole becomes the same phase and the FG output voltage becomes zero. The straight line connecting the center and the pair of FG extraction line element pairs arranged close to each other were set to have the same phase.

The technical means of the fifth invention for solving the above-mentioned problems is to drive an FG wiring line element pair which is a pair of two conductive patterns connected in series to an FG coil and arranged in close proximity to each other. The number of magnetic poles for use is 2N and K pairs (K <2
N and K are odd numbers), and an FG lead-out line element pair having substantially the same shape as this FG lead-out line element pair is provided, and the closest FG lead-out line element pair or FG lead-out line element pair is 180 / The phase was set to be shifted by N * a (a is an odd number) degrees.

[0036]

The operation of the technical means of the first invention is that when the magnetic pole boundary between the FG power generation line element and the FG magnetic pole is in the same phase and the FG output voltage becomes 0, the FG power generation line element and the driving magnetic pole are driven. By setting the magnetic pole boundaries so that they do not have the same phase, the phase at which the level of noise generated in the FG power generation line element by the driving magnetic pole becomes the highest shifts from the phase at which the FG output voltage becomes 0. It is suppressed that the noise component due to the magnetic pole for use fluctuates the cycle T of the FG signal. As a result, even if the outer diameter of the driving magnetic pole is increased so that the driving magnetic pole is close to the FG coil, the high precision F
Since the G signal can be obtained, the torque characteristics of the motor can be secured even when a magnet material having a lower energy product is used, and the cost of the motor can be reduced.

The operation of the technical means of the second invention is F
The magnetic pole boundary between the G generator line element and the FG magnetic pole is in the same phase,
When the G output voltage becomes 0, the pair of FG extraction line elements arranged close to each other and the magnetic pole boundary of the driving magnetic pole are set so as not to be in the same phase. Since the phase at which the level of noise generated in the line element pair becomes highest deviates from the phase at which the FG output voltage becomes 0, noise components due to the driving magnetic poles are suppressed from varying the cycle T of the FG signal. As a result, even if the FG coil and the FG magnetic pole are provided on the inner circumference side of the driving magnetic pole, it is possible to obtain a highly accurate FG signal. Also, since the outer diameter of the driving magnetic pole can be made large,
Even if a magnet material having a lower energy product is used, the torque characteristics of the motor can be secured, and the cost of the motor can be reduced.

The function of the technical means of the third invention is F
The magnetic pole boundary between the G generator line element and the FG magnetic pole is in the same phase,
When the G output voltage becomes 0, the straight line connecting the center of the PG magnetic pole and the rotation center and the FG power generation line element are set to have the same phase, so that the PG magnetic pole generates the FG power generation line element. The phase at which the noise level is stable is F
Since the G output voltage coincides with the phase of 0, the amount by which the noise component due to the PG magnetic pole fluctuates the cycle T of the FG signal is stabilized. As a result, even if the relative phase between the PG magnetic pole and the FG magnetic pole slightly shifts or the circumferential length of the PG magnetic pole becomes large, it is possible to obtain an FG signal having a stable waveform.

The operation of the technical means of the fourth invention is F
The magnetic pole boundary between the G generator line element and the FG magnetic pole is in the same phase,
When the G output voltage becomes 0, a straight line connecting the center of the PG magnetic pole and the center of rotation and a pair of FGs arranged close to each other
By setting the lead wire element pair to have the same phase, the FG output voltage is 0 when the phase at which the noise level generated in the FG lead wire element pair by the PG magnetic pole is the lowest.
The noise component due to the PG magnetic pole suppresses the fluctuation of the cycle T of the FG signal. As a result, even if the relative phase between the PG magnetic pole and the FG magnetic pole slightly shifts or the circumferential length of the PG magnetic pole becomes large, it is possible to obtain a highly accurate FG signal.

The operation by the technical means of the fifth invention is F
A pair of FG routing line elements, in which two conductive patterns connected in series to the G coil are arranged in close proximity to each other to form a pair, are provided as K pairs (K <2N, K
Is an odd number), and an FG lead-out line element pair having substantially the same shape as this FG lead-out line element pair is provided, and the closest FG lead-out line element pair or FG lead-out line element pair is 180
/ N * a (a is an odd number) is set by shifting the phase so that the noise generated in the FG lead-out line element pair by the driving magnetic pole is the closest to the FG lead-out line element pair or the FG lead-out line element pair. They cancel each other.
Therefore, even if the FG coil and the FG magnetic pole are provided on the inner circumference side of the drive magnetic pole, it is possible to obtain a highly accurate FG signal. Further, since the outer diameter of the driving magnetic pole can be made large, the torque characteristic of the motor can be secured even when a magnet material having a lower energy product is used, and the cost of the motor can be reduced.

[0041]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The first aspect of the first invention will now be described with reference to the drawings
An example will be described. The description of the points that are the same as those of the conventional configuration will be omitted.

FIG. 1 is a plan view of a stator substrate and a rotor magnet of the FG section in the first embodiment of the first invention. As shown in the figure, the FG magnetic poles 9 are arranged on the outer peripheral side of the rotor magnet 6, and here, 16 poles are magnetized at equal pitches. In addition, the FG coil 1 having 16 FG power generation line elements 5 is arranged on the stator substrate 7 so as to face the FG coil. Further, the trapezoidal shaped main coil 18 has three
Six pieces are arranged on the stator substrate 7 in order to perform the full-wave drive.

On the other hand, the driving magnetic poles 8 are magnetized on the inner peripheral side of the rotor magnet 8 so as to have eight poles at equal pitches. Where F
The opening angle 2 of one pole of the FG magnetic pole 9 is set so that the G magnetic pole boundary 9a and the driving magnetic pole boundary 8a are not in the same phase with each other.
It is offset by half of 2.5 degrees, or 11.25 degrees.

The operation of the motor having the FG thus configured will be described below. The magnetic fluxes of the FG magnetic pole 9 and the driving magnetic pole 8 interlink with the FG coil 1 arranged on the stator substrate 7. Here, when the rotor magnet 6 is rotationally driven in a predetermined direction by the rotational biasing force generated between the rotor magnet 6 and the main coil 18, the magnetic flux interlinking with the FG coil 1 changes due to the rotation, so the FG coil 1 Generates an FG signal having a frequency proportional to the rotation speed of the rotor magnet 6. Where FG
At the phase where the power generation line element 5 coincides with the FG magnetic pole boundary 9a, the driving magnetic pole boundary 8a and the FG power generation line element 5 are 11.25.
The phase will be shifted by degrees. FG in this embodiment
The output waveform is shown by the solid line in FIG. Although the peak value of the FG output waveform is fluctuated because the noise component is superimposed, the fluctuation of the FG cycle T, which is the most important for the FG output, is small.

The level of noise generated in the FG power generation line element 5 by the drive magnetic pole 8 is the highest because the FG power generation line element 5 is located at the position where the rate of change of the magnetic flux density of the drive magnetic pole 8 is the highest. It was when I did. That is, the noise level becomes maximum when the FG power generation line element 5 is located at the drive magnetic pole boundary 8a. However, in the present embodiment, the drive magnetic pole 8 and the FG magnetic pole 9 are set so that the noise level is not maximized in the phase where the FG output crosses 0 as described above.
The relative phase with is set. Therefore, in this embodiment, the FG signal is not disturbed in its cycle, and an extremely stable signal can be obtained. This means that the magnetic poles for driving 8 are less likely to be affected by the unevenness of the magnetization pitch, and the assembling accuracy can be relaxed.

In the conventional example, in order to prevent the influence of the driving magnetic pole 8 on the FG power generation line element 5, the outer diameter of the driving magnetic pole 8 is considerably smaller than the outer diameter of the rotor magnet 6. Although it has been set, according to the present invention, it is not necessary and the outer diameter of the drive magnetic pole 8 can be increased, so that the torque characteristic is improved. That is, it is possible to use a material having a smaller energy product as the material of the rotor magnet 6 while ensuring the accuracy of the FG signal, and it is possible to reduce the cost of parts.

Next, a second embodiment of the first invention will be described. FIG. 2 is a perspective view of a circumferentially opposed motor according to a second embodiment of the first invention. In the rotor yoke 13,
The rotor magnet 6 is integrally fixed. On the upper part of the rotor magnet 6, there is provided a driving magnetic pole 8 which is magnetized into 8 poles. In addition, the lower part of the FG is multi-polarized with 16 poles.
A magnetic pole 9 is provided. Here, the drive magnetic pole boundaries 8a and F
The G magnetic pole boundaries 9a are set to be offset by 11.25 degrees from each other.

On the other hand, six main coils 18 are arranged on the drive magnetic pole 8 with a radial gap therebetween, and the main coils 18 are integrated by resin molding to form the stator 11. Also,
On the FG magnetic pole 9, a comb-tooth-shaped FG coil 1 composed of 16 FG power generation line elements 5 is arranged with a radial gap therebetween, and the FG coil 1 is fixed to a stator 11. That is, the FG section in the embodiment constitutes a circumferentially opposed type full circumference integral type.

The operation of the motor provided with the FG thus constructed will be described below. The magnetic flux of the FG magnetic pole 9 is linked to the FG coil 1. Here, the rotor magnet 6 is the main coil 1
When rotationally driven in a predetermined direction by the rotational urging force generated between the FG coil 1 and the magnetic flux linked to the FG coil 1, the magnetic flux linked to the FG coil 1 changes.
Generates an FG signal having a frequency proportional to the rotation speed of the.

Since the FG power generating line element 5 is also interlinked with the leakage magnetic flux of the driving magnetic pole 8 though slightly, noise is generated by the driving magnetic pole 8 and is superimposed on the FG output.
The FG output waveform in this embodiment is shown by the solid line in FIG.

The level of noise generated in the FG power generation line element 5 by the driving magnetic pole 8 is highest.
This is when the FG power generation line element 5 is located at the place where the rate of change of the magnetic flux density is maximized. That is, the noise level is F
It becomes maximum when the G power line element 5 is located at the drive magnetic pole boundary 8a. However, in the present embodiment, the relative phase between the drive magnetic pole 8 and the FG magnetic pole 9 is set so that the noise level does not become maximum at the phase where the FG output crosses 0 as described above. Therefore, in this embodiment, the FG signal is not disturbed in its cycle T, and an extremely stable signal can be obtained.

As described above, it is possible to obtain a high-accuracy FG signal even in the case of the circumferentially opposed all-round integral type FG.

Although the number of poles of the FG magnetic pole 9 is 16 and the number of poles of the driving magnetic pole 8 is 8 in the above embodiment, it is obvious that the present invention is not limited to this. For example, the number of poles of the FG magnetic pole 9 is 16, and the number of poles of the driving magnetic pole 8 is 1
It is clear that it is good to have a second prize. FIG. 7 shows a plan view of an example of the rotor magnet 6 in this case. As shown in this example, the angle formed by the drive magnetic pole boundary 8a and the FG magnetic pole boundary 9a varies depending on the location, but may be set so that the closest phase is 3.75 degrees. That is,
The FG magnetic pole boundary of the FG magnetic pole 9 multipolarized to 2M poles (where M ≠ N and M is a natural number) with respect to the drive magnetic pole boundary 8a of the driving magnetic pole 8 multipolarized to 2N poles. 9a may be magnetized so as to shift the phase by θ degrees (θ = 90 · (1 / N−1 / M)).

Further, in the above embodiment, the driving magnetic pole 8 and the FG magnetic pole 9 are provided on one rotor magnet 6, but
The present invention is not limited to this, and both may be separate magnets.

Further, in the present invention, the FG magnetic pole 9 is replaced with the driving magnetic pole 8.
The FG output terminal 3 is provided closer to the inner peripheral side than the FG coil 1
It can also be applied to the one having the configuration provided on the inner peripheral side.

Next, an embodiment of the second invention will be described. The description of the points that are the same as those of the conventional configuration will be omitted.

FIG. 3 shows an FG according to an embodiment of the second invention.
FIG. 3 is a plan view of a stator substrate and a rotor magnet of a part. As shown in the figure, the FG magnetic poles 9 are arranged on the inner peripheral side of the rotor magnet 6, and here, 16 poles are magnetized at equal pitches.
Corresponding to this, the FG coil 1 having 16 FG power generation line elements 5 is also arranged on the inner peripheral side of the rotor magnet 6. On the other hand, the driving magnetic poles 8 are multi-pole magnetized on the outer peripheral side of the rotor magnet 6 with eight poles at equal pitches. The drive magnetic pole 8
The inner diameter dimension of the drive magnetic pole 8 is set to be larger than the outer diameter dimension of the FG power generation wire element 5 so that the leakage magnetic flux of the above does not interlink with the FG power generation wire element 5.

A pair of FG output terminals 3 are arranged on the outer peripheral side of the stator substrate 7. Further, a pair of FG lead-out wire elements 2 which relay between the FG output terminal 3 and the FG coil 1 is provided. The FG lead wire pair 2 is composed of two conductive patterns that are close to each other. Further, the FG power generation line element 5 matches the FG magnetic pole boundary 9a,
In the phase where the output is 0, this FG lead wire element pair 2 is half of the opening angle 22.5 degrees of one pole of the FG magnetic pole 9 so that it does not coincide with the drive magnetic pole boundary 8a, only 11.25 degrees. The phases are shifted.

The operation of the motor having the FG constructed as described above will be described below. The magnetic flux of the FG magnetic pole 9 interlinks with the FG coil 1 arranged on the stator substrate 7. Here, when the rotor magnet 6 is rotationally driven in a predetermined direction by the rotational biasing force generated between the rotor magnet 6 and the main coil 18, the magnetic flux interlinking with the FG coil 1 changes due to the rotation, so that F
An FG signal having a frequency proportional to the rotation speed of the rotor magnet 6 is generated in the G coil 1.

Since the FG lead wire element pair 2 is linked to the leakage magnetic flux of the drive magnetic pole 8, noise is generated by the drive magnetic pole 8 and is superimposed on the FG output. The FG output waveform in this embodiment is shown by the solid line in FIG. Although the peak value of the FG output waveform is fluctuated because the noise component is superimposed, the fluctuation of the FG cycle T, which is the most important for the FG output, is small.

The level of noise generated in the FG lead-out wire element pair 2 by the driving magnetic pole 8 is highest when the change rate of the magnetic flux density of the driving magnetic pole 8 is the largest. When is located. That is, the noise level becomes maximum when the FG lead wire pair 2 is located at the drive magnetic pole boundary 8a. However, in the present invention, the relative phase between the drive magnetic pole 8 and the FG lead-out wire element pair 2 is set so that the noise level is not maximized in the phase where the FG output crosses 0 as described above.
Therefore, in this embodiment, the FG signal is not disturbed in its cycle, and an extremely stable signal can be obtained.

Therefore, even if the FG magnetic pole 9 is arranged on the inner peripheral side of the driving magnetic pole 8, it is possible to suppress disturbance of the FG cycle and obtain a highly accurate FG signal. Also,
Since the drive magnetic pole 8 can be arranged on the outer peripheral side of the rotor magnet 6, it is possible to secure the torque characteristics of the motor even if a ferrite-based magnet material having a low energy product is used, thus reducing the cost of parts. It becomes possible to plan.

It should be noted that the present invention is not limited to the plane-opposed full-circumferential integral type FG, but can be naturally applied to the circumferential-opposed full-circumferential integral type FG, and similar effects can be obtained. .

Further, the relative phase between the FG magnetic pole 9 and the driving magnetic pole 8 is not limited to that shown in the present embodiment, but the FG magnetic pole boundary 9a and the driving magnetic pole boundary 8a as in the above-mentioned first invention. And may be shifted by 11.25 degrees. In this case, even if a noise component due to the driving magnetic pole 8 is superposed on the FG power generation line element 5, it does not affect the FG cycle, so that the inner diameter of the driving magnetic pole 8 can be set small. It is possible to further improve the torque characteristic of.

Although the number of poles of the FG magnetic pole 9 is 16 and the number of poles of the driving magnetic pole 8 is 8 in the above embodiment, it is obvious that the present invention is not limited to this. For example, it is obvious that the number of poles of the FG magnetic pole 9 may be 16, the number of poles of the driving magnetic pole 8 may be 12, and the like. FG in this case
FIG. 8 shows a plan view of the stator substrate and the rotor magnet of the part. The angle formed by the drive magnetic pole boundary 8a and the FG magnetic pole boundary 9a in this figure differs depending on the location, and is set to 3.75 degrees in the closest phase. That is, the FG of the FG magnetic pole 9 multipolarized to 2M poles (where M ≠ N and M is a natural number) with respect to the drive magnetic pole boundary 8a of the drive magnetic pole 8 multipolarized to 2N poles. The magnetic pole boundary 9a is θ degrees (θ = 90.
Magnetization is performed by shifting the phase by (1 / N-1 / M)).

In this example, the FG lead wire element pair 2 is set to have the same phase as the FG power generating wire element 5.
Therefore, in the rotation phase where the FG output becomes 0, the FG lead-out line element pair 2 does not overlap the drive magnetic pole boundary 8a, so that the noise component due to the drive magnetic pole 8 generated in the FG lead-out line element pair 2 has its level. Is suppressed, and it is possible to obtain a highly accurate FG signal.

Further, in the above embodiment, the driving magnetic pole 8 and the FG magnetic pole 9 are provided on one rotor magnet 6, but
The present invention is not limited to this, and both may be separate magnets.

Further, according to the present invention, the FG magnetic pole 9 is replaced with the driving magnetic pole 8.
Provided on the outer peripheral side of the FG output terminal 3 and the drive magnetic pole 8
The present invention is also applicable to a structure in which the FG lead wire element pair 2 is provided on the inner peripheral side and the FG lead wire element pair 2 is arranged therebetween.

Next, an embodiment of the third invention will be described.
Note that the description of the points that are the same as those of the conventional configuration will be omitted.

FIG. 4 shows an FG according to an embodiment of the third invention.
FIG. 3 is a plan view of a stator substrate and a rotor magnet of a part. As shown in the figure, the FG magnetic pole 9 is arranged on the outer peripheral side of the rotor magnet 6 and is magnetized to have 16 poles in this case. On the other hand, the driving magnetic poles 8 are multi-pole magnetized into eight poles at an equal pitch on the inner peripheral side of the rotor magnet 8. Here, the FG magnetic pole boundary 9a and the driving magnetic pole boundary 8a are set to F so that they are not in the same phase with each other.
The G magnetic pole 9 is displaced by one half of the opening angle of 22.5 degrees, that is, 11.25 degrees. Also, the PG magnetic pole 10
Is provided on one S pole of the drive magnetic pole 8. Here, the FG power generation line element 5 matches the FG magnetic pole boundary 9a, and F
In the rotation phase where the G output becomes 0, the straight line connecting the center of the PG magnetic pole 10 and the rotation center and the FG power generation line element 5 are set to have the same phase. Here, the PG magnetic pole 10
The phase FG magnetic pole boundary 9a is shifted to the N pole side by one minute angle Δθ.

The operation of the motor thus constructed will be described below. The magnetic flux of the FG magnetic pole 9 interlinks with the FG coil 1 arranged on the stator substrate 7. Here, due to the rotation biasing force generated between the rotor magnet 6 and the main coil 18,
When the FG is driven to rotate in a predetermined direction, FG is generated by the rotation.
Since the magnetic flux linked to the coil 1 changes, an FG signal having a frequency proportional to the rotation speed of the rotor magnet 6 is generated in the FG coil 1.

Here, the FG power generation line element 5 is the FG magnetic pole boundary 9
In the rotation phase that matches a and the FG output voltage becomes 0,
The straight line connecting the center of the PG magnetic pole 10 and the center of rotation is in the same phase as the FG power generation line element 5. By the way, the PG magnetic pole 10
As shown in FIG. 13, the distribution of only the magnetic flux density is most stabilized at the center of the PG magnetic pole 10 and sharply changes near the magnetic pole boundary of the PG magnetic pole 10. That is, in the phase where the FG output voltage becomes 0, the leakage magnetic flux of the PG magnetic pole 10 becomes FG.
Since it interlinks with the power generation line element 5, noise is generated, but the noise level is extremely stable.

Further, in the present invention, the FG magnetic pole boundary 9a of the phase where the PG magnetic pole 10 is provided is shifted to the N pole side by Δθ. This is because the S pole component of the FG magnetic pole 9 is generated by shifting the FG magnetic pole boundary 9a in order to cancel the leakage magnetic flux of the N pole component of the PG magnetic pole 10. Here, another F of the FG magnetic pole boundary 9a in this portion
Since the positional deviation with respect to the G magnetic pole boundary 9a is determined only by the processing accuracy of the magnetizing yoke (not shown), the PG magnetic pole 10 is not displaced as in the conventional case. Even if the magnetization of the PG magnetic pole 10 is slightly deviated from that of the FG magnetic pole 9, since the magnetic flux density distribution of the PG magnetic pole 10 is located near the flat position, the intensity of the leakage magnetic flux from the PG magnetic pole is almost the same. It does not change.

Therefore, unlike the conventional example, the noise level due to the PG magnetic pole does not fluctuate for each part, and it is possible to obtain a stable FG output waveform with high accuracy and a constant shape with little variation among products. Become.

Further, even if the area of the PG magnetic pole 10 becomes large or the relative phase between the PG magnetic pole 10 and the FG magnetic pole 9 is slightly shifted, the noise level is extremely stable, so that the assembling accuracy can be eased. You can do it. Also, P
Since the area of the G magnetic pole 10 may be increased, it is possible to increase the PG output.

In this embodiment, the PG magnetic pole 10 is
Although it is provided on the drive magnetic pole 8, the present invention is not limited to this. For example, only the FG magnetic pole 9 and the PG magnetic pole 10 are provided on the rotor magnet 6, and the drive magnetic pole 8 of the motor is separately dedicated. The magnet may be provided.

Further, the PG magnetic pole 10 is provided on the same magnet as the FG magnetic pole 9, but the present invention is not limited to this, and a dedicated PG magnet is separately provided, for example, the outer peripheral portion of the rotor yoke 13 or the like. The same effect can be obtained even if it is arranged at.

Further, the present invention is not limited to the plane-opposed full-circumferential integral type FG, and can naturally be applied to the configuration of the circumferential-opposed full-circumferential integral type FG, and similar effects can be obtained. You can

The relative phase between the FG magnetic pole 9 and the driving magnetic pole 8 is not limited to that shown in this embodiment, but the FG magnetic pole boundary 9 as in the embodiment of the second invention described above.
You may make a and the magnetic pole boundary 8a for a drive match. In this case, the outer diameter of the driving magnetic pole 8 may be slightly reduced.

Further, in the above embodiment, the FG magnetic pole 9
However, the present invention is not limited to this, and any number of poles may be set.

Further, according to the present invention, the FG magnetic pole 9 is replaced by the PG magnetic pole 10.
It can also be applied to a device having a configuration provided on the inner peripheral side.

Next, an embodiment of the fourth invention will be described.
Note that the description of the points that are the same as those of the conventional configuration will be omitted.

FIG. 5 shows an FG according to an embodiment of the fourth invention.
FIG. 3 is a plan view of a stator substrate and a rotor magnet of a part. As shown in the figure, the FG magnetic poles 9 are arranged on the inner peripheral side of the rotor magnet 6, and here, 16 poles are magnetized at equal pitches.
On the other hand, the driving magnetic poles 8 are multi-pole magnetized into eight poles at an equal pitch on the outer peripheral side of the rotor magnet 8. Here, the FG magnetic pole boundary 9
The a and the driving magnetic pole boundary 8a are shifted by half of the opening angle 22.5 degrees of one pole of the FG magnetic pole 9, that is, by 11.25 degrees so as not to be in the same phase. Also, P
The G magnetic pole 10 is provided on one S pole of the driving magnetic poles 8.

A pair of FG output terminals 3 is arranged on the outer peripheral side of the stator substrate 7. Further, a pair of FG lead-out wire elements 2 which relay between the FG output terminal 3 and the FG coil 1 is provided. The FG lead wire pair 2 is composed of two conductive patterns that are close to each other. Further, the FG power generation line element 5 matches the FG magnetic pole boundary 9a,
In the phase where the output is 0, the straight line connecting the center of the PG magnetic pole 10 and the center of rotation and the FG lead wire element pair 2 are set to be in the same phase.

The operation of the motor thus constructed will be described below. The magnetic flux of the FG magnetic pole 9 interlinks with the FG coil 1 arranged on the stator substrate 7. Here, due to the rotation biasing force generated between the rotor magnet 6 and the main coil 18,
When the FG is driven to rotate in a predetermined direction, FG is generated by the rotation.
Since the magnetic flux linked to the coil 1 changes, an FG signal having a frequency proportional to the rotation speed of the rotor magnet 6 is generated in the FG coil 1.

Here, the FG power generation line element 5 is the FG magnetic pole boundary 9
In the rotation phase that matches a and the FG output voltage becomes 0,
The straight line connecting the center of the PG magnetic pole 10 and the center of rotation is in the same phase as the FG extraction line element pair 2. With the FG output waveform and the PG magnetic pole in the present embodiment configured as described above,
The noise waveforms superimposed on the leader line element pair 2 are shown in FIG. 12 by a solid line and a broken line, respectively. As shown in FIG. 12, the noise level generated by the leakage magnetic flux of the PG magnetic pole 10 becomes 0 in the rotation phase where the FG output becomes 0. because,
In this phase, the magnetic flux density distribution of the PG magnetic pole 10 is shown in FIG.
This is because the noise voltage generated in the FG extraction line element pair 2 which is most stabilized as shown in FIG.

That is, in this embodiment, the FG signal is not disturbed in its cycle T, and an extremely stable signal can be obtained. This means that the PG magnetic pole 1
It is irrelevant even if the area of 0 becomes large, and even if the relative phase between the PG magnetic pole 10 and the FG magnetic pole 9 is slightly shifted, FG
The cycle means that it is less susceptible to that,
Assembling accuracy can be relaxed. Further, since the area of the PG magnetic pole 10 may be increased,
There is also an effect that the PG output can be increased.

In this embodiment, the PG magnetic pole 10 is
Although it is provided on the drive magnetic pole 8, the present invention is not limited to this. For example, only the FG magnetic pole 9 and the PG magnetic pole 10 are provided, and the drive magnetic pole 8 of the motor is separately provided with a dedicated magnet. It may be.

Further, the present invention is not limited to the plane-opposed full-circumferential integral type FG, and can naturally be applied to the configuration of the circumferential-opposed full-circumferential integral type FG, and the same effect can be obtained. You can

Further, the PG magnetic pole 10 is provided on the same magnet as the FG magnetic pole 9, but the present invention is not limited to this, and a dedicated PG magnet is separately provided, for example, the outer peripheral portion of the rotor yoke 13 or the like. The same effect can be obtained even if it is arranged at.

Further, the relative phase between the FG magnetic pole 9 and the driving magnetic pole 8 is not limited to that shown in this embodiment, but the FG magnetic pole boundary 9 as in the embodiment of the second invention described above.
It is also applicable to the case where a and the drive magnetic pole boundary 8a are matched. In this case, the outer diameter of the driving magnetic pole 8 may be slightly reduced.

Although the number of poles of the FG magnetic pole 9 is 16 and the number of poles of the driving magnetic pole 8 is 8 in the above-mentioned embodiment, the present invention is not limited to this and any number of poles can be set. It is clear that you can do it.

Further, according to the present invention, the FG magnetic pole 9 is replaced by the PG magnetic pole 10.
The FG output terminal 3 is provided on the outer peripheral side of the PG magnetic pole 10
The present invention is also applicable to a structure in which the FG lead-out wire element pair 2 is provided on the inner peripheral side of the FG lead-out wire element pair 2 and is disposed therebetween.

Next, an embodiment of the fifth invention will be described.
Note that the description of the points that are the same as those of the conventional configuration will be omitted.

FIG. 6 shows an FG according to an embodiment of the fifth invention.
FIG. 3 is a plan view of a stator substrate and a rotor magnet of a part. As shown in the figure, the FG magnetic poles 9 are arranged on the inner peripheral side of the rotor magnet 6, and here, 16 poles are magnetized at equal pitches.
On the other hand, the driving magnetic poles 8 are multi-pole magnetized into eight poles at an equal pitch on the outer peripheral side of the rotor magnet 8. Here, the FG magnetic pole boundary 9
The a and the driving magnetic pole boundary 8a are shifted by half of the opening angle 22.5 degrees of one pole of the FG magnetic pole 9, that is, by 11.25 degrees so as not to be in the same phase. Also, P
The G magnetic pole 10 is provided on one pole of the driving magnetic pole 8.

A pair of FG output terminals 3 is provided on the outer peripheral side of the stator substrate 7. Further, a pair of FG lead-out wire elements 2 which relay between the FG output terminal 3 and the FG coil 1 is provided. The FG lead wire pair 2 is composed of two conductive patterns that are close to each other. In addition, it has substantially the same shape as this FG lead wire element pair 2,
The FG wiring line element pair 4 connected in series to the G coil 1
One pair is provided at a phase 45 degrees apart from the FG lead wire pair 2. It should be noted that although separated by 45 degrees here, this corresponds to an odd multiple of the opening angle of one pole of the drive magnetic pole 8. Further, the FG lead-out line element pair 2 and the FG lead-out line element pair 4 are made 180 degrees out of phase with each other to make a total of two pairs of F
A G wiring line element pair 4 is provided. That is, the FG routing line element pairs 4 are arranged in an odd number in total.

The operation of the motor thus constructed will be described below. The magnetic flux of the FG magnetic pole 9 interlinks with the FG coil 1 arranged on the stator substrate 7. Here, due to the rotation biasing force generated between the rotor magnet 6 and the main coil 18,
When the FG is driven to rotate in a predetermined direction, FG is generated by the rotation.
Since the magnetic flux linked to the coil 1 changes, an FG signal having a frequency proportional to the rotation speed of the rotor magnet 6 is generated in the FG coil 1.

Here, the FG power generation line element 5 is the FG magnetic pole boundary 9
In the rotation phase that matches a and the FG output voltage becomes 0,
Noise is superimposed on each of the FG leading wire element pair 2 and the FG leading wire element pair 4 due to the leakage magnetic flux of the driving magnetic pole 8. However, the closest FG routing line element pair 4 here
Alternatively, the pair of FG lead-out wire elements 2 is an odd multiple of the opening angle of one pole of the driving magnetic pole 8 (45 degrees in this embodiment).
Since they are separated from each other, the noise components respectively superposed on each other have opposite phases to each other and the noise levels are exactly the same, so that they are completely canceled from each other.

That is, in this embodiment, the FG signal is not disturbed in its cycle, and a very stable signal can be obtained. Therefore, even if the FG magnetic pole 9 is arranged on the inner peripheral side of the drive magnetic pole 8, it is possible to suppress disturbance of the FG cycle and obtain a highly accurate FG signal. Further, since the drive magnetic pole 8 can be arranged on the outer peripheral side of the rotor magnet 6, it is possible to secure the torque characteristics of the motor even if a ferrite-based magnet material having a low energy product is used. It is possible to go down.

The present invention is not limited to the plane-opposed full-circumferential integral type FG, but can be naturally applied to the circumferential-opposed full-circumferential integral type FG, and similar effects can be obtained. .

Further, according to the present invention, the FG magnetic pole 9 is replaced with the driving magnetic pole 8.
Provided on the outer peripheral side of the FG output terminal 3 and the drive magnetic pole 8
The present invention can be applied to a structure in which the FG lead-out wire element pair 2 and the FG lead-out wire element pair 4 are provided on the inner peripheral side, and the FG lead-out wire element pair 2 and the FG drawing line element pair 4 are arranged between them.

In the phase where the FG output becomes 0,
The phase relationship between the drive magnetic pole 8 and the FG lead-out wire element pair 2 or the FG lead-out wire element pair 4 is not limited to that illustrated in the present embodiment. For example, the drive magnetic pole boundary 8a and the FG lead-out wire element pair. Even if 2 and the same phase, a noise canceling effect can be expected.

In this embodiment, the FG routing line element pair 4 is used.
Although three pairs are provided, it is not limited to this. For example, only one pair may be provided, or five or seven pairs may be provided.

Although the number of poles of the FG magnetic pole 9 is 16 and the number of poles of the driving magnetic pole 8 is 8 in the above embodiment, it is obvious that the present invention is not limited to this. As an example, the number of poles of the FG magnetic pole 9 may be 16, the number of poles of the driving magnetic pole 8 may be 12, and the like. FIG. 7 shows a plan view of an example of the rotor magnet 6 in this case. The angle formed by the drive magnetic pole boundary 8a and the FG magnetic pole boundary 9a in this example differs depending on the location, and is set to 3.75 degrees in the closest phase. In this case, the closest F
The G lead-out line element pair 4 or the FG lead-out line element pair 2 is an opening angle of one pole of the drive magnetic pole 8 (in this case, 30).
It is clear that we only need to open an odd number of degrees.

It is clear that the first to fifth inventions may be used individually or in appropriate combination.

Furthermore, the present invention is not applied only to the rotary head drum, but can be applied to any device using a motor equipped with FG and PG.

[0107]

According to the motor provided with the FG according to the first aspect of the present invention, when the magnetic pole boundaries of the FG power generation line element and the FG magnetic pole are in the same phase and the FG output voltage becomes 0, the FG power generation line element becomes By setting the magnetic pole boundaries of the driving magnetic poles so that they are not in the same phase, the phase at which the level of noise generated in the FG power generation line element by the driving magnetic poles becomes the highest is F
Since the G output voltage deviates from the phase where it becomes 0, the noise component due to the driving magnetic pole is suppressed from changing the cycle T of the FG signal. As a result, even if the outer diameter of the driving magnetic pole is large so that the driving magnetic pole is close to the FG coil, a highly accurate FG signal can be obtained.
Even if a magnet material having a lower energy product is used, the torque characteristics of the motor can be secured, and the cost of the motor can be reduced.

Further, according to the motor having the FG according to the second aspect of the invention, when the magnetic pole boundaries of the FG power generation line element and the FG magnetic pole are in the same phase and the FG output voltage becomes 0, they are arranged close to each other. By setting the pair of FG lead-out wire pairs and the magnetic pole boundary of the driving magnetic pole not to be in the same phase, the phase where the level of noise generated in the FG lead-out wire pair by the driving magnetic pole becomes the highest However, since the phase in which the FG output voltage becomes zero is deviated, fluctuations in the cycle T of the FG signal due to noise components due to the driving magnetic poles are suppressed. As a result, even if the FG coil and the FG magnetic pole are provided on the inner peripheral side of the driving magnetic pole, it is possible to obtain a highly accurate FG signal. Further, since the outer diameter of the driving magnetic pole can be made large, the torque characteristic of the motor can be ensured even when a magnet material having a lower energy product is used, and the cost of the motor can be reduced. .

Further, according to the motor having the FG according to the third aspect of the invention, when the magnetic pole boundaries of the FG power generation line element and the FG magnetic pole are in the same phase and the FG output voltage becomes 0, the center of the PG magnetic pole is By setting the straight line connecting the rotation center and the FG power generation line element to have the same phase, the phase at which the level of noise generated in the FG power generation line element by the PG magnetic pole is most stable is the FG output voltage. Since the phase becomes 0, the amount by which the noise component due to the PG magnetic pole changes the period T of the FG signal is stabilized. As a result, even if the relative phase between the PG magnetic pole and the FG magnetic pole is slightly shifted or the circumferential length of the PG magnetic pole is increased, the FG having a stable waveform is generated.
There is an effect that it becomes possible to obtain a signal.

Further, according to the motor having the FG according to the fourth aspect of the invention, when the magnetic pole boundary between the FG power generation line element and the FG magnetic pole is in the same phase and the FG output voltage becomes 0, the PG magnetic pole is at the center of the magnetic pole. By setting the straight line connecting the center of rotation and the pair of FG extraction line element pairs arranged close to each other so as to have the same phase, the level of noise generated in the FG extraction line element pair by the PG magnetic pole Is the lowest phase,
Since the phase in which the FG output voltage becomes 0 matches, the noise component due to the PG magnetic pole is suppressed from changing the cycle T of the FG signal. As a result, even if the relative phase between the PG magnetic pole and the FG magnetic pole is slightly shifted or the circumferential length of the PG magnetic pole is increased, it is possible to obtain a highly accurate FG signal.

Further, according to the motor having the FG according to the fifth aspect of the invention, the pair of FG wiring line elements in which two conductive patterns connected in series to the FG coil are arranged close to each other, K pairs (K <2N and K is an odd number) are provided for the number 2N of magnetic poles for driving, and an FG lead-out line element pair having substantially the same shape as this FG lead-out line element pair is provided, and the closest FG lead-out is provided. The line element pairs or the FG extraction line element pairs are set with a phase shift of 180 / N * a (a is an odd number) degrees, so that the noise generated in the FG extraction line element pairs by the driving magnetic poles is The FG leading line element pair or the FG leading line element pair that are closest to each other are canceled. Therefore, even if the FG coil and the FG magnetic pole are provided on the inner circumference side of the drive magnetic pole, it is possible to obtain a highly accurate FG signal. Further, since the outer diameter of the driving magnetic pole can be made large, there is an effect that the torque characteristic of the motor can be ensured and the cost of the motor can be reduced even if a magnet material having a lower energy product is used. .

[Brief description of drawings]

FIG. 1 is a plan view of a stator substrate and a rotor magnet of an FG section according to a first embodiment of the first invention.

FIG. 2 is a perspective view of a circumferentially opposed motor according to a second embodiment of the first invention.

FIG. 3 is a plan view of a stator substrate and a rotor magnet of an FG section according to an embodiment of the second invention.

FIG. 4 is a plan view of a stator substrate and a rotor magnet of an FG section according to an embodiment of the third invention.

FIG. 5 is a plan view of a stator substrate and a rotor magnet of an FG section according to an embodiment of the fourth invention.

FIG. 6 is a plan view of a stator substrate and a rotor magnet of an FG section according to an embodiment of the fifth invention.

FIG. 7 is a plan view of a rotor magnet having a 12-pole magnetized driving magnetic pole and a 16-pole magnetized FG magnetic pole.

FIG. 8 is a plan view of a stator substrate and a rotor magnet of an FG portion in the case of having a 12-pole magnetized driving magnetic pole and a 16-pole magnetized FG magnetic pole.

FIG. 9 is an FG signal waveform diagram in an ideal state.

FIG. 10 is an FG signal waveform diagram when a noise component due to a driving magnetic pole superimposed on an FG power generation line element does not affect the FG cycle.

FIG. 11 is an FG signal waveform diagram when a noise component due to a driving magnetic pole superimposed on an FG lead wire pair does not affect the FG cycle.

FIG. 12 is an FG signal waveform diagram when a noise component due to a PG magnetic pole superimposed on an FG lead wire pair does not affect the FG cycle.

FIG. 13 is a magnetic flux density distribution diagram of a PG magnetic pole.

FIG. 14 is an FG signal waveform diagram when a noise component due to a driving magnetic pole superimposed on an FG power generation line element changes the FG cycle.

FIG. 15 is an FG signal waveform diagram when a noise component due to a driving magnetic pole superimposed on an FG lead wire pair changes the FG cycle.

FIG. 16 is an FG signal waveform diagram when the noise component due to the PG magnetic pole superimposed on the FG lead wire pair changes the FG cycle.

FIG. 17 is a plan view of a stator substrate and a rotor magnet of an FG portion in the first conventional example.

FIG. 18 is a cross sectional view of a rotary head drum using the motor.

FIG. 19 is a plan view of a stator substrate and a rotor magnet of an FG section in a second conventional example.

FIG. 20 is a plan view of a stator substrate and a rotor magnet of an FG portion in a third conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 FG coil 2 FG lead wire element pair 3 FG output terminal 4 FG routing wire element pair 5 FG power generating wire element 6 rotor magnet 7 stator substrate 8 driving magnetic pole 8a driving magnetic pole boundary 9 FG magnetic pole 9a FG magnetic pole boundary 10 PG magnetic pole Reference Signs List 11 stator 12 shaft 13 rotor yoke 14 rotating drum 15 fixed drum 16 thrust receiving member 17 rotary transformer 18 main coil 19 fixed yoke

Claims (5)

[Claims] 1. A shaft and a shaft which is rotatably supported about the shaft and is 2N in a circumferential direction.
(N is a natural number) A multi-pole magnetized annular first magnetic pole, and is configured to rotate in a pair with the first magnetic pole about the axis, and 2 M (M Rotation of the second magnetic pole, which has an annular second magnetic pole that is multi-pole magnetized (≠ N and M are natural numbers), and a plurality of pairs of power generating line elements that are arranged to face the second magnetic pole. A comb-teeth-shaped generating coil that generates a signal having a frequency proportional to a rotational angular velocity by motion, and the generating line element of the generating coil and the first coil in a rotation phase at which the generated voltage of the generating coil becomes zero. The motor is characterized in that the relative phase of the first magnetic pole and the second magnetic pole is set so that the magnetic pole boundary of the magnetic pole is not in the same phase. 2. A shaft and a shaft which is rotatably supported about the shaft and has a diameter of 2N in the circumferential direction.
(N is a natural number) Multi-pole magnetized first magnetic pole, and is configured to rotate in a pair with the first magnetic pole about the axis, and 2M (M ≠ N, M is a natural number) and has a second magnetic pole that is multi-polarized, and a plurality of pairs of power generating line elements that are arranged to face the second magnetic pole. Proportional to the rotational angular velocity due to the rotational movement of the second magnetic pole. Through a comb-teeth-shaped power generation coil that generates a signal of a specified frequency, a pair of lead wire elements that are electrically connected to the power generation coil, and are arranged close to each other, and the pair of lead wire element pairs. A pair of signal output terminals electrically connected to the power generation coil, wherein the pair of lead wire pairs form a magnetic pole boundary of the first magnetic pole in a rotation phase where the power generation voltage of the power generation coil becomes 0. A motor characterized by not having the same phase. 3. A shaft, an annular multipole magnetic pole that is rotatably supported about the shaft and is magnetized in the circumferential direction, and rotates in a pair with the multipole magnetic pole. A position detecting magnetic pole provided at least at one location on or near the multipolar magnetic pole, and a plurality of pairs of power generating line elements arranged facing the multipolar magnetic pole,
A comb-teeth-shaped generating coil that generates a signal of a frequency proportional to the rotational angular velocity by the rotational movement of the multi-pole magnetic pole, and the position-detecting magnetic pole is in a rotation phase in which the generated voltage of the generating coil is zero. The motor is characterized in that a straight line connecting the center of the power generating coil and the center of rotation has the same phase as the power generating line element of the power generating coil. 4. A shaft, an annular multipole magnetic pole that is rotatably supported about the shaft and is magnetized in the circumferential direction, and rotates in a pair with the multipole magnetic pole. A position detecting magnetic pole provided at least at one location on or near the multipolar magnetic pole, and a plurality of pairs of power generating line elements arranged facing the multipolar magnetic pole,
A comb-teeth-shaped power generation coil that generates a signal of a frequency proportional to the rotational angular velocity by the rotational movement of the multi-pole magnetic pole, and a pair of lead wire elements electrically connected to the power generation coil and arranged close to each other. A pair and a pair of signal output terminals electrically connected to the generator coil via the pair of lead wire elements, and for position detection in a rotation phase where the generated voltage of the generator coil becomes 0. A motor in which a straight line connecting the center of the magnetic pole and the center of rotation has the same phase as that of the pair of lead wire elements. 5. A shaft and a shaft which is rotatably supported around the shaft and has a diameter of 2N in the circumferential direction.
(N is a natural number) Multi-pole magnetized first magnetic pole, and is configured to rotate in a pair with the first magnetic pole about the axis, and 2M (M ≠ N, However, M is a natural number) and has a second magnetic pole that is multi-polarized, and a plurality of pairs of power generating line elements that are arranged so as to face the second magnetic pole. The rotational angular velocity is generated by the rotational movement of the second magnetic pole. A comb-shaped generator coil that generates a signal of a frequency proportional to the two, and two conductive patterns that are electrically connected in series to the generator coil are arranged close to each other to form a pair, K pair (K
<2N and K is an odd number) routing wire element pairs, two signal output terminals electrically connected to the generator coil, and substantially the same shape as the routing wire element pair, and these two signal outputs The lead wire element pair or the lead wire element pair that are closest to each other are 180 / N * a (a is Odd number)
A motor that is characterized by a phase shift of 1 degree.