JP3381068B2 - Phase detector - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for detecting the phase of a rotating drum in a VTR device for recording or reproducing information signals such as audio signals and video signals by winding a magnetic tape. It relates to the device.

[0002]

2. Description of the Related Art Conventionally, a rotary head device in a VTR, DAT or the like is constructed as shown in FIG. 18, a rotary head device 1 includes a fixed drum 2, a rotary shaft 3 rotatably supported by a bearing incorporated in the fixed drum 2 around a center line of the fixed drum 2, and the rotary shaft 3. 3, a rotary drum 4 integrally attached to the rotary drum 3, and a motor 5 provided at the lower end of the rotary shaft 3.
It consists of and.

Here, the motor 5 includes a rotor 6 mounted below the fixed drum 2 at the lower end of the rotary shaft 3,
It is composed of a stator substrate 7 attached to the fixed drum 2 above the rotor 6, and a yoke 8 attached to the rotating shaft 3 above the stator substrate 7. Further, a rotor magnet 6a is attached to the upper surface of the rotor 6.

As shown in FIG. 19, the rotor magnet 6a is magnetized so that twelve magnetized portions, that is, N poles and S poles are alternately arranged along the circumferential direction, and a set of magnets is also formed. The magnetized portion, that is, the N pole 6b and the S pole 6c are formed so as to project inward.

On the other hand, the stator substrate 7 has a plurality of drive coils (not shown) arranged at equal intervals along the circumferential direction, and as shown in FIG. , A phase detection pattern 7a formed so as to project inside the magnetized portion of the rotor magnet 6a.

As shown in FIG. 19, the phase detection pattern 7a has the N pole 6b and the S pole 6 of the rotor magnet 6a.
A phase detection coil (in the illustrated case, a one-turn coil) is formed in a region facing a portion protruding inward of c.

According to the rotary head device 1 constructed as described above, when reproducing, by energizing each drive coil on the stator substrate 7, the magnetic field generated in this drive coil is generated by the rotor magnet. It acts on each of the north and south poles of 6a. As a result, the rotor 6 is rotated together with the rotary shaft 3 and the rotary drum 4, and the rotary drum 4
A signal detected from the magnetic tape by a magnetic head (not shown) provided in the is output to the outside through a mechanism (not shown).

During recording, the rotary drum 4 rotates in the same manner as during reproduction, and an electric signal from a control circuit (not shown) is output to the magnetic head via a mechanism (not shown). Writing to the magnetic tape will be performed.

In this case, since the rotor magnet 6a has a portion in which the N pole 6b and the S pole 6c protrude inward, when the rotor 6 rotates, the N pole 6b and the S pole 6c of the rotor magnet 6a are rotated. The portion protruding inward passes through the phase detection pattern 7a. Thus, every time the rotor 6 makes one revolution, the phase detection pattern 7a
Since one pulse voltage is generated in the above, the rotation of the rotor 6 and its phase are detected by detecting this pulse voltage.

[0010]

However, in such a rotary head device 1, the rotor magnet 6 is used.
Since a has a portion in which the N pole 6b and the S pole 6c protrude inward, the weight balance of the rotor magnet 6a and the rotor 6 is lost. Therefore, there is a problem that vibration occurs when the rotor 6 rotates.

In addition, a part of the magnetized portion of the rotor magnet 6a is formed so as to protrude outward, and a phase detection pattern is formed on the stator substrate 7 so as to face the protruding portion, or Similarly, when a separate magnet is attached to the inner or outer diameter of the rotor magnet 6a, and the phase detection pattern is formed on the stator substrate 7 so as to face the separate magnet, the rotation of the rotor is similarly performed. Vibration is generated along with.

On the other hand, a phase detecting device as shown in FIG. 20, for example, can be considered. That is, in FIG. 20, the phase detection device 9 magnetizes a part of the magnetized portions of the rotor magnet 6a, that is, the N poles 6b and the S poles 6c, to the inner peripheral portions of the magnets to the opposite poles, and also to the stator substrate 7 Above, two phase detection coils 7 of opposite windings are arranged facing each other inside and outside the magnetized portion of the rotor magnet 6a.
A phase detection pattern 7d including b and 7c is provided.
Other configurations are the same as those of the phase detection device 1 shown in FIGS. 18 and 19.

Since the phase detection pattern 7d intersects on the stator substrate 7 on the way, the through hole 7 formed in the stator substrate 7 at this intersection.
It is connected to the back surface of the stator substrate 7 via the terminals e and 7f.

According to the phase detecting device 9 having such a structure, when reproducing, by energizing each drive coil on the stator substrate 7, the magnetic field generated in this drive coil is generated by the rotor magnet. 6a each north pole and S
It acts on the pole. As a result, the rotor 6 is rotated together with the rotary shaft 3 and the rotary drum 4, and the signal detected by the magnetic head by a magnetic head (not shown) provided on the rotary drum 4 is transferred via a mechanism (not shown). It is output to the outside.

During recording, the rotary drum 4 rotates in the same manner as during reproduction, and an electric signal from a control circuit (not shown) is output to the magnetic head via a mechanism (not shown). Writing to the magnetic tape will be performed.

In this case, since the N pole 6b and the S pole 6c of the rotor magnet 6a are provided with magnetized portions of opposite poles on the inner peripheral portion, when the rotor 6 rotates, the rotor magnet 6a is rotated.
The S pole and N pole of the inner peripheral portion of the N pole 6b and the S pole 6c of a and the N pole and S pole of the outer peripheral portion are the phase detection pattern 7d.
Will pass through the inner phase detection coil 7c and the outer phase detection coil 7b. Thus, each time the rotor 6 makes one rotation, pulse voltages in opposite directions are generated in the phase detection coils 7b and 7c of the phase detection pattern 7d. And each phase detection coil 7b, 7c is
Since it is cross-connected, the phase detection pattern 7d
, A pulse voltage higher than the pulse voltage generated in each of the phase detection coils 7b and 7c is generated. Thus, by detecting this pulse voltage, the rotation of the rotor 6 and its phase can be detected more accurately.

However, such a phase detecting device 9
, The phase detection pattern 7d corresponds to the stator substrate 7
Through the through-holes provided on the back side of the stator substrate 7 so as to intersect with each other. Therefore, the stator substrate 7 needs to use a double-sided substrate, which causes a problem of high cost.

In view of the above points, the present invention can be manufactured at a low cost with a simple structure, and the accurate phase detection can be performed by obtaining a high output detection signal without losing the rotor weight balance. It is an object of the present invention to provide a phase detection device.

[0019]

SUMMARY OF THE INVENTION According to the present invention, the above object is to provide a magnetized portion which is magnetized so that N poles and S poles are alternately arranged along the circumferential direction and which is adjacent in at least one place. A rotor magnet in which at least a part of the magnetic poles is deformed and magnetized to have opposite polarities on the outer diameter side or the inner diameter side, a stator substrate fixedly arranged facing the rotor magnet, and the rotor magnet of the rotor magnet on the stator substrate. Two phase detections in the same winding direction, which are completely opposed to the deformed magnetized region and are formed at positions shifted by 180 electrical degrees of the magnetizing period on the inner side and outer side in the radial direction and connected in series And a phase detection pattern including a coil.

In the phase detection device according to the present invention, preferably, the phase detection coil is configured as a one-turn coil.

In the phase detection device according to the present invention, preferably, the phase detection coil is configured as a two-turn coil.

In the phase detector according to the present invention, preferably, the rotor magnet is deformed and magnetized to have opposite poles on the outer diameter side or the inner diameter side of both adjacent magnetic poles.

In the phase detector according to the present invention, preferably, the rotor magnet is deformed and magnetized to have opposite polarities on the outer diameter side of one of the adjacent magnetic poles and the inner diameter side of the other magnetic pole.

[0024]

According to the above construction, when the magnetic poles of the rotor magnet pass in opposition to the phase detection pattern, the phase detection signals of opposite electromotive forces generated in the phase detection coils of the phase detection pattern cancel each other out. Will be done. Further, when the deformed and magnetized portion passes in opposition to the phase detection pattern, the electromotive force generated in each phase detection coil of the phase detection pattern is in the same direction and synchronized, so that a larger phase A detection signal will be obtained.

When the phase detection coil is constructed as a two-turn coil, a larger phase detection signal is obtained as compared with the one-turn coil.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to FIGS. It should be noted that the examples described below are suitable specific examples of the present invention, and therefore, various technically preferable limitations are given, but the scope of the present invention particularly limits the present invention in the following description. Unless otherwise stated, the present invention is not limited to these modes.

FIG. 1 shows an embodiment of a rotary head device incorporating a phase detector according to the present invention. In FIG. 1, the rotary head device 10 includes a fixed drum 11, a rotary shaft 12 rotatably supported by a bearing incorporated in the fixed drum 11 around a center line of the fixed drum 11, and a rotary shaft 12. The rotary drum 13 is integrally attached to the rotary drum 12, and the motor 14 is provided at the lower end of the rotary shaft 12.

Here, the motor 14 includes a rotor 15 mounted below the fixed drum 11 at the lower end of the rotary shaft 12, a stator substrate 16 mounted on the fixed drum 11 above the rotor 15, and A yoke 17 mounted on the rotating shaft 12 above the stator substrate 16.
It consists of and. Further, a rotor magnet 18 is attached to the upper surface of the rotor 15.

The rotor magnet 18 is magnetized so that an even number, for example, 12 magnetized portions, that is, N poles and S poles are alternately arranged along the circumferential direction, and as shown in FIG. A part of the magnetized portion, that is, the N pole 18a and the S pole 18
The inner half of b is deformed and magnetized to have opposite poles, that is, S pole 18c and N pole 18d. In this case, the deformable magnetizing unit 1
8c and 18d have a circumferential length of the rotor magnet 1
It has an electrical angle of 180 degrees (180 ° e) with a magnetization period of 8. The deformed magnetized portion of the rotor magnet is not limited to the configuration shown in FIG. 4, and it is sufficient that at least one portion has a reverse pole on the inner peripheral side and the outer peripheral side.

On the other hand, the stator board 17 is
It has a plurality of coils (not shown) arranged at equal intervals along the circumferential direction, and as shown in FIG. 4, is arranged so as to project to the magnetized portion of the rotor magnet 18. The detected phase detection pattern 20 is included.

This phase detection pattern 20 is, as shown in FIG. 4, the deformed magnetized portions 18c, 1 of the rotor magnet 18.
Two phase detection coils 21 and 2 formed in a region facing the region 8d and a region outside this region, each having the same magnetizing period in the same winding direction and an electrical angle of 180 degrees.
It consists of two.

Here, the phase detection coils 21 and 22 are
Is a pattern formed on the stator substrate 16,
The detection signals are connected in series with each other, and the sum of the detection signals thereof is taken out from the terminals 20a and 20b to the outside, and the detection signals are displaced from each other by an electrical angle of 180 degrees in the magnetization period. Furthermore, the phase detection coils 21 and 22 are respectively
The radial lengths L1 and L2 are selected as follows. That is, in the regions other than the deformable magnetized portions 18c and 18d, the phase detection signals of the two phase detection coils 21 and 22 are in opposite directions, and the combined signals thereof cancel each other. There is. Then, the above L1 and L
When 2 is added, it is approximately equal to the radial width of the rotor magnet 18 on the ring. As a result, the phase detection coil 2
1, 22 are rotor magnets 18 on the stator substrate 16.
It is located at a position completely opposite to. In other words, the phase detection coils 21 and 22 are connected to the rotor magnet 1
From the radial width of 8, it does not substantially fit. As a result, according to the phase detection coils 21 and 22, a larger output can be obtained when the deformed and magnetized portions of the rotor magnet 18 facing each other pass.

The rotary head device 10 according to this embodiment is constructed as described above, and the motor 14 is used for recording.
By energizing the drive coil formed on the stator substrate 16, the magnetic field generated in the drive coil acts on each of the N pole and the S pole of the rotor magnet 18. As a result, the rotor 15 is rotated together with the rotary shaft 12 and the rotary drum 13, and an electric signal from the outside such as a control circuit is transmitted to the rotary drum 13 via a mechanism (not shown) and provided on the rotary drum 13. Output to a magnetic head (not shown). As a result, this magnetic head writes on a magnetic tape (not shown). During reproduction, the signal detected by this magnetic head is transferred from the rotary drum 13 to the fixed drum 11.
And is output to an external control circuit or the like.

Here, in general, the electromotive force E generated in the coil is L, the radial length of the magnetized portion of the rotor magnet 18 is V, the rotational speed at the magnetized portion is V, and the magnetic flux density due to the magnetized portion is B. When I did

[Equation 1] Therefore, when the deformed magnetized portions 18c and 18d pass through the respective phase detection coils 21 and 22, the electromotive force E1 of the entire phase detection pattern 20 is as shown in FIG.

[Equation 2] Becomes Thus, the pulse voltage of the electromotive force E1 is applied between the terminals 20a and 20b of the phase detection pattern 20 each time the deformed magnetized portions 18c and 18d pass through the phase detection coils 21 and 22 as the rotor 15 rotates. Will be output.

For reference, the phase detection coil is
When the electromotive force of the entire phase detection pattern is calculated when it is not displaced inward and outward in the radial direction, as shown in FIG. 8, on the stator substrate 16 so as to face the deformed and magnetized portion 18e of the rotor magnet 18. And two phase detection coils 23a, 23b formed in the same direction and arranged side by side in the circumferential direction.
Electromotive force E2 generated in the phase detection pattern 23 composed of
Is

[Equation 3] Becomes Therefore, the pulse voltage of the electromotive force E1 is applied between the terminals 20a and 20b of the phase detection pattern 20 each time the deformed magnetized portions 18c and 18d pass through the phase detection coils 21 and 22 as the rotor 15 rotates. Will be output.

Thus, in the phase detector 10,
By arranging the phase detection coils 21 and 22 so as to be displaced inward and outward in the radial direction, a double electromotive force can be obtained.

FIG. 11 shows a modification of the phase detection pattern 20. That is, in FIG. 11, in the phase detection pattern 23, the inner phase detection coil 23a and the outer phase detection coil 23b are configured as two turns with respect to the one turn phase detection pattern 20 shown in FIG. There is. In this case, since the entire phase detection pattern 23 is formed on the front surface of the stator substrate 16, it is not necessary to form a pattern on the back surface of the stator substrate 16, and therefore a through hole is also unnecessary.

By using such a phase pattern 23, an electromotive force about twice as large as that in the case of the phase detection pattern 20 of FIG. 4 can be obtained.

FIG. 12 shows another example of the structure of the deformed magnetized portion of the rotor magnet. In FIG. 12, a part of the magnetized portion of the rotor magnet 24, that is, a part of the N pole 24a on the outer peripheral side in the circumferential direction and a part of the S pole 24b on the inner peripheral side in the circumferential direction are The opposite poles, that is, the S pole 24d and the N pole 24c, are deformed and magnetized. In this case, the deformable magnetizing portion 2 operates in the same manner as the rotor magnet 18 of FIG.
Since the area of the portion having the opposite polarity due to 4c and 24d is smaller than that of the rotor magnet 18 of FIG.
Torque down due to the deformed magnetized portions 24c and 24d is reduced.

13 and 14 show modifications of the phase detection pattern. Phase detection pattern 2 shown in FIG.
0 indicates that the phase detection coils 21 and 22 are displaced by an electrical angle of 180 degrees and have a length of an electrical angle of 180 degrees with respect to the circumferential direction, but the phase detection pattern has a circumferential direction of each phase detection coil. If the shift is 180 degrees in electrical angle, the length of each phase detection pattern in the circumferential direction is not limited to 180 degrees in electrical angle, and as shown in FIG.
, The phase detection coils 25a and 25b may each have an electrical angle θa degrees smaller than 180 degrees in the circumferential direction. Further, as shown in FIG. The detection coils 26a and 26b are
Each may have an electrical angle θb degree greater than 180 electrical degrees in the circumferential direction.

Further, the above-mentioned phase detection pattern 20,
23, 25, and 26, the phase detection coils are arranged so as to be offset from each other by an electrical angle of 180 degrees in a magnetizing cycle, but the invention is not limited to this, and as shown in FIG. The respective phase detection coils 27a and 27b have the following equations in the circumferential direction.

[Equation 4] May be shifted by the electrical angle θc given by.

Further, the phase detection pattern is constructed as shown in FIGS. That is, in FIG.
The phase detection pattern 28 is the phase detection pattern 20 of FIG.
A part of the phase detection coil 20b outside the

[Equation 5] Are arranged so as to spread in the counterclockwise direction by the electrical angle θd given by. In this case, the portion 28c extending in the radial direction of the phase detection coil 28b is displaced counterclockwise by an electrical angle θd degrees to the portion 28d, as shown by the solid line, so that the electromotive force generated in these portions 28c, 28d is reduced. The direction is the same. Therefore, the output of the phase detection pattern 28 is the same as that of the phase detection pattern 20 of FIG.

Further, in FIG. 17, the phase detection pattern 29 is formed by shifting a part of the phase detection coil 20b outside the phase detection pattern 20 of FIG. 4 so as to be spread clockwise by the electrical angle θd degrees. There is. In this case, the portion 29c extending in the radial direction of the phase detection coil 29b is shifted clockwise to the portion 29d by the electrical angle θd degrees as shown by the solid line, so that these portions 29c, 29d.
The direction of the electromotive force generated in is the same. Therefore, the output of the phase detection pattern 28 is the phase detection pattern 20 of FIG.
Is the same as.

Here, for example, when there is a constraint such as a space on the stator substrate 16, the above-described FIGS.
By using the phase detection patterns 27, 28, and 29 of No. 7, the space on the stator substrate 16 is effectively used to form the phase detection pattern.

As described above, in the above-described embodiment, when each magnetic pole of the rotor magnet passes in opposition to the phase detection pattern, the phase detection signal of the reverse electromotive force generated in each phase detection coil of the phase detection pattern is , And when the deformed and magnetized portions pass while facing the phase detection pattern, the electromotive force generated in each phase detection coil of the phase detection pattern is in the same direction. , A larger phase detection signal can be obtained. In particular, since the phase detection coil is arranged so as to completely face the rotor magnet and is positioned within the width of the rotor magnet in the radial direction, a large output can be obtained from this phase detection coil.

In this case, since the rotor magnet itself does not have a protrusion on the outside or inside, it is formed point-symmetrically. Therefore, the weight balance of the rotor magnet and the rotor is not lost, and the vibration due to the loss of weight balance is not generated when the rotor is rotated. Further, since the two phase detection coils are formed on the stator substrate and are connected in series by the pattern formed on the stator substrate, the double-sided substrate is used as the stator substrate and the through holes are provided in the stator substrate. The cost is reduced because it is not necessary.

In the above embodiment, the phase detector 10 is used.
Is incorporated in the rotary head device, but is not limited to this, and it is clear that the present invention can be applied to a phase detection device for detecting the rotational phase of various devices having other rotary members. Is.

[0048]

As described above, according to the present invention, it is possible to manufacture at a low cost with a simple structure, to obtain a high-output detection signal, and moreover, without losing the weight balance of the rotor. Thus, it is possible to provide a phase detection device in which accurate phase detection is performed.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of a rotary head device equipped with a phase detection device according to the present invention.

FIG. 2 is a schematic plan view showing a positional relationship between a rotor magnet and a phase detection pattern in the rotary head device of FIG.

FIG. 3 is a schematic plan view of a rotor magnet in the rotary head device of FIG.

4 is an enlarged plan view of a phase detection pattern in the rotary head device of FIG.

5 is a schematic plan view showing a rotor magnet and a phase detection pattern when the rotor is rotating in the rotary head device of FIG.

6 is a partially enlarged plan view showing a rotor magnet and a phase detection pattern at the time of phase detection in the rotary head device of FIG.

FIG. 7 is a graph showing detection signals by the rotor magnet of FIG. 2 and a phase detection pattern.

FIG. 8 is a schematic plan view showing a rotor magnet and a phase detection pattern in a configuration in which the phase detection pattern is not displaced in the radial direction with respect to FIG.

9 is a partially enlarged plan view showing the rotor magnet of FIG. 8 and the phase detection pattern when the phase is detected.

10 is a graph showing detection signals by the rotor magnet of FIG. 8 and a phase detection pattern.

11 is an enlarged plan view showing a modified example of the phase detection pattern of FIG.

12 is an enlarged plan view showing a modified example of the rotor magnet of FIG.

13 is an enlarged plan view showing a modified example of the phase detection pattern of FIG.

FIG. 14 is an enlarged plan view showing a modified example of the phase detection pattern of FIG.

15 is an enlarged plan view showing a modified example of the phase detection pattern of FIG.

16 is an enlarged plan view showing a modified example of the phase detection pattern of FIG.

FIG. 17 is an enlarged plan view showing a modified example of the phase detection pattern of FIG.

FIG. 18 is a schematic cross-sectional view showing an example of a rotary head device including a conventional phase detection device.

19 is a schematic plan view showing a relationship between a rotor magnet and a phase detection pattern in the rotary head device of FIG.

FIG. 20 is a schematic plan view showing the relationship between a rotor magnet and a phase detection pattern according to another configuration of the phase detection device.

[Explanation of symbols]

Reference Signs List 10 rotary head device 11 fixed drum 12 rotary shaft 13 rotary drum 14 motor 15 rotor 16 stator substrate 17 back yoke 18 rotor magnets 18c, 18d deformed magnetized portion 20 phase detection pattern 21 inner phase detection coil 22 outer phase detection coil 23 , 25, 26, 27, 28, 29 phase detection patterns 23a, 25a, 26a, 27a, 28a, 29a inner phase detection coils 23b, 25b, 26b, 27b, 28b, 29b inner phase detection coil 24 rotor magnet 24c, 24d Deformed magnetizing part

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G11B 15/467 H02K 29/08

Claims (5)

(57) [Claims] 1. A N pole and S pole along the circumferential direction are magnetized to alternating, and, adjacent at least one location, at least a portion of the magnetic pole is the outer diameter side or inner magnetized part Side, a rotor magnet having a deformed and magnetized region that is deformed and magnetized to the opposite pole, a stator substrate fixedly arranged facing the rotor magnet, and a deformed and magnetized region of the rotor magnet on the stator substrate. Completely opposed to each other and within the radial direction
Each is formed in the radial side and a position shifted by an electrical angle of 180 degrees of wear磁周life in outer diameter side, and a phase and a phase detection patterns consisting of two phase detection coil in the same winding direction are connected in series Detection device. 2. The phase detection device according to claim 1, wherein the phase detection coil is configured as a one-turn coil. 3. The phase detection device according to claim 1, wherein the phase detection coil is configured as a two-turn coil. 4. The phase detection according to claim 1, wherein the rotor magnet is deformed and magnetized to have opposite poles on the outer diameter side or the inner diameter side of both adjacent magnetic poles. apparatus. 5. The rotor magnet is deformed and magnetized to have opposite poles on the outer diameter side of one of the adjacent magnetic poles and the inner diameter side of the other magnetic pole among the adjacent magnetic poles. The phase detection device according to any one of 1.