JPS6356864A - Rotation detecting device - Google Patents

Abstract

PURPOSE:To miniaturize a rotary detector by constituting a frequency generator by a rotor and a detection coil and constituting a pulse signal generator by the rotor and a detection element. CONSTITUTION:A magnet 23 acting like the frequency generator is used in common, an nonmagnetizing part 40 is formed at a part of the magnet 23 and the detection element 33 for detecting a pulse detection signal (PG signal) is provided to part of the detection coil 32. Since the element for detecting a sinusoidal detection signal (FG) signal is used in common for the element for a PG signal, a single pole magnet for the PG signal is not required. The miniaturization of the rotary detector is attained because of the reduction in the number of components and the possibility of arranging the detection element 33 on a mount base 31.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field 1] The present invention relates to a rotating device suitable for application to a floppy disk drive device or a rotating drum drive system of a VTR.

[Prior Art] In floppy disks, VTRs, and the like, data is recorded according to a predetermined format, and the recorded data is reproduced according to the recording format.

Such reference signals for recording and reproduction, that is, the relative positional relationship of the recording and reproduction head with respect to the recording medium disk (magnetic sheet) and magnetic tape, are usually provided in a floppy disk or a rotating magnetic head device that drives the magnetic tape. It uses signals obtained from a frequency generator, or even a pulse generator.

In most cases, a frequency generator or a pulse generator is provided in conjunction with a drive motor for a floppy disk or a rotating magnetic head device, and an example thereof is shown in FIG.

In the figure, reference numeral 1 denotes a motor as a rotating device, and a rotating part 20 is attached and fixed to one end of a rotating shaft 2 so as to rotate integrally with the rotating shaft 2.

A rotation detecting section 30 is disposed opposite to the rotating section 20 and the motor 1 with a predetermined gap therebetween.

As shown in the figure, the rotating section 20 is composed of a rotating disk 21 having an inward flange 22 and a ring-shaped magnet 23 fixedly attached to the inside of the rotating disk 21. Therefore, when this rotating portion 20 is viewed from above, it has a shape as shown in FIG. 15.

As shown in the figure, the magnet 23 fixed on the rotating disk 21 is constituted by a permanent magnet consisting of a plurality of magnetic poles (N and S poles) magnetized at a predetermined pitch in the circumferential direction.

A monopolar magnet 24 for generating pulses, which will be described later, is provided on a part of the circumferential surface of the rotating disk 21.

As shown in FIG. 14, the rotation detection unit 30 is mounted in a predetermined manner on a substrate 31 (the motor is fixed to a member).
A detection coil 32 is formed in the detection coil 32.
As shown in FIG. 16, the magnet 23 is mounted in a comb-teeth shape so as to face the magnet 23 with respect to the substrate 31. The number of comb-teeth coils 32b formed can be selected to be half the number of magnetic poles.

On the other hand, a detection element 33 is disposed on the outer peripheral surface of the substrate 31 so as to face the unipolar magnet 24 .

In this configuration, the magnet 23 and the detection coil 32 constitute a frequency generator, and the unipolar magnet 24 and the detection element 3 constitute a frequency generator.
3 constitutes a pulse generator.

Therefore, by driving the motor 1, the output terminal 32a of the detection coil 32 receives a sinusoidal detection signal a (FG (No. 8) as shown in FIG. At the terminal 33a, a pulsed detection signal b (PG flaw signal is obtained as shown in the figure).
It goes without saying that the rotational speed of the motor can be detected using the double signal, and the rotational phase of the motor can be detected using the PG flaw signal.

[Problems to be Solved by the Invention] By the way, in the rotating device 10 configured in this way, P
G (In order to detect No. 3, as mentioned above, F G
(In addition to the No. 3 detection means, the unipolar magnet 24 and the detection element 3
3 must be provided.

Therefore, these elements are mounted on the rotating disk 21 or on the substrate 3.
1, this poses a problem in that it is difficult to downsize the rotation detection device itself, and the cost increases due to an increase in the number of detection components.

Therefore, the present invention proposes a rotating device that solves these conventional problems with a simple structure and is small in size and can reduce costs.

[Technical means for solving the problems] In order to solve the above-mentioned problems, a rotating device according to the present invention includes a rotating part connected to a rotating shaft of a rotating device, and a predetermined gap between the rotating part and the rotating part. and a rotation detecting section that is held and placed opposite to each other.

The rotating part is composed of a magnet having a plurality of magnetic poles and a non-magnetized part provided in a part of the magnet.

The rotation detection section is characterized by being provided with a detection coil formed in an O-tooth shape for detecting the magnetized portion of the magnet, and a detection element for detecting the non-magnetized portion. .

[Action 1 The rotating part and the detection coil constitute a frequency generator, and the rotating part and the detection element constitute a pulse signal generator.

Even if there is a non-magnetized part in the magnet, when the motor is driven to rotate, the detection coil will output a detection signal a (continuous signal) in the same state as if the non-magnetized part was also magnetized, that is, FG (8
number is obtained. The fact that a sine wave signal is detected even from the non-magnetized portion is due to the integral action of the detection coil.

Since the detection element is provided only in a part of the detection coil, there is no integral action as in the detection coil. Therefore, the detection signal b (discontinuous signal) can only be obtained from the magnetized portion of the magnet passing through the detection element. In other words, the non-magnetized portion becomes a no-signal section.

By signal processing the detection signals a and b corresponding to the non-magnetized portions, the PG signal d is obtained, so that the rotational phase of the motor can be detected easily and reliably.

[Example] Next, a case in which the rotating device 10 according to the present invention is applied to the above-mentioned drive device will be described in detail with reference to FIG. 1 and subsequent figures.

FIG. 1 is a configuration diagram of essential parts showing an example of a rotating device 1o according to the present invention, and this rotating device 10 is also arranged to face a rotating section 20 attached to a rotating shaft 2 of a motor 1. and a rotation detection section 30.

The rotating section 20 is composed of a rotating disk 21 and a magnet 23 attached to the rotating disk 21.

As shown in FIG. 2, the magnet 23 is composed of a permanent magnet with a plurality of magnetic poles magnetized in the circumferential direction so as to be located on a predetermined radius, and has a non-magnetized part at the negative part. 40 are provided.

In the non-magnetized portion 40, a portion corresponding to one to several magnetic poles is left in a non-magnetized state. In this example, as shown in the figure, three magnetic pole portions are used as the non-magnetized portion 40.

On the other hand, as shown in FIGS. 1 and 3, the rotation detecting section 30 includes a detecting coil 32 and a detecting element 33, which are mounted on the lower surface of a substrate 31 by printing or the like.

That is, as shown in FIG. 3, the detection coil 32 is configured such that the coil is formed in a comb-like shape in the circumferential direction, and the number of the tii-toothed coils 32b is, for example, equal to the number of magnets. The number of magnetic poles is set to about half of the number of magnetic poles of 23.

Then, a detection element 33 is completely formed in a part of this detection coil 32. As the detection element 33, a simple coil, a magnetic head, a Hall element (including a Hall IC), a magnetoresistive element, etc. can be used.

What is shown in FIG. 3 is a case where coils are used, and one
Only a turn is formed, and output terminals 33a are led out from both ends of the turn.

The formation position of the detection element 33 is not particularly limited.

FIG. 4 is a sectional view including the detection element 33 in FIG.
This is the case where 3 is formed.

In the case of A in the same figure, for example, the detection coil 3 is printed and wired.
An insulating layer 36 such as 5i02 is provided on the upper surface of the sensor 2, and a coil constituting the detection element 33 is printed at a predetermined position on the upper surface, in this example, directly above the detection coil 32.

FIG. 4B shows a case where the detection element 33 is formed inside the detection coil 32. In this case, the detection element 33 is detected at the same time as the detection coil 32 is formed, or only one turn is detected after the detection coil 32 is formed. This is where the element 33 is formed.

The detection element 33 is mounted on the substrate 31 as shown in FIG.
It can also be formed on a surface opposite to the surface on which the detection coil 32 is formed.

In this case, the magnet 23 of the rotating section 20 and the detection coil 32 of the rotation detecting section 30 constitute a frequency generator, and the non-magnetized section 40 of the rotating section 20 and the detecting element of the rotation detecting section 30 constitute a frequency generator. 33 constitutes a pulse signal generator.

Now, the signal detection operation of the rotating device 10 configured as described above will be explained in detail with reference to FIG. 6.

Figure A shows a state in which the detection coil 32 is extended on one plane. Similarly, if the magnet 23 is extended on one plane, it will become as shown in Figure B, and this magnet 23 will reach the position shown in Figure C after T time.

Therefore, a sinusoidal detection signal a shown in the figure is obtained at both terminals 32a of the detection coil 32.

This detection signal a is used as an FG signal.

Here, this detection number 43a is detected as a continuous signal despite the presence of the non-magnetized portion 40 of the magnet 23.

This is because the detection coil 32 is arranged to face all of the magnetic poles of the magnet 23, and each comb-tooth coil 32b of the detection coil 32 crosses each magnetic pole. Even if there is, the magnetic pole always crosses the comb-teeth coil 32b except for this non-magnetized portion 40.

Therefore, the voltage induced in the comb-tooth coil facing the magnetic pole is integrated and output to the output terminal 32a.
As a result, even if the non-magnetized portion 40 exists in a part of the magnet 23, the detection signal a becomes a continuous sine wave signal.

Using this detection signal a, the rotational speed of the motor 1 and the like are calculated.

On the other hand, since the detection element 33 is only formed to correspond to one 4fit coil 32b of the detection coils 32, it does not have an integral action like the detection coil 32, and acts like a magnetized portion of the magnet 23. A signal corresponding to the non-magnetized portion 40 is detected.

That is, as shown in FIG. 6E, since no detection signal is obtained at the time when the non-magnetized portion 40 passes the detection element 33, the detection signal is discontinuous.

Note that since the detection signal a is obtained by integrating the outputs obtained from each comb-teeth coil 32b, its peak value is higher than the peak value of the detection signal S.

In order to generate one pulse per rotation of the motor 1, that is, a PG multiplied signal, from this discontinuous detection signal, it is necessary to perform arithmetic processing on the above-mentioned continuous detection signal a and discontinuous detection signal S. .

- As an example, a PG detection circuit 50 as shown in FIG. 7 may be used.

As described above, the detection coil 32 outputs a continuous detection signal a (FIG. 8A), and the detection element 33 outputs a detection signal b (FIG. 8A) in which the signal becomes discontinuous in correspondence with the non-magnetized portion 40 Figure B) is output. The detection signal a is supplied to a subtraction circuit 51 composed of a differential amplifier or the like, and the detection signal a is supplied to one input terminal, that is, one terminal, of the subtraction circuit 51 in an opposite phase state via a predetermined amplifier 52. Ru.

As a result, since the detection signal a and the detection signal S are subtracted in the same phase state, only the detection signal C (C in the figure) corresponding to the non-magnetized portion 40 is output.

Note that when a region corresponding to three magnetic poles is assigned as the region of the non-magnetized portion 40, as shown in FIG. Some signal will be detected.

Therefore, the subtracted output C has a waveform as shown in FIG. 8C. Therefore, this subtracted output C is waveform-shaped by the waveform shaping circuit 53. This waveform shaped output d (D in the figure) is used as a PG multiplied signal.

When using a Hall element as the detection element 33,
It can be installed in a position as shown in FIG.

In this case, the Hall element may be attached to either the upper or lower surface of the substrate 31.

Further, when only one magnetic pole formation position is selected as the non-magnetized portion 40, the detection operation is as shown in FIG. However, this is a case where a Hall element is used as the detection element 33. Since the detection operation is the same as in Fig. 6,
A detailed explanation will be omitted.

FIG. 11 shows an example in which two non-magnetized portions are formed at symmetrical positions.

That is, as shown in FIG. 11, in this example, there are non-magnetized portions 40 and 41 at 1800 opposing positions, corresponding to three magnetic poles.
is formed.

On the other hand, as shown in FIG.
Single coil 33b constituting No. 3.

33c is formed.

When the rotating unit 20 and the rotation detecting unit 30 are configured in this way to form the rotating device 10, the detection signal obtained from the detecting element 33 is as shown in FIG.
(two PG multiplied signal pulses) are obtained per revolution of .

This PG multiplied signal can be used, for example, as a head switching pulse of a rotating magnetic head device.

In addition, although the area corresponding to one or three magnetic poles has been illustrated as the non-magnetized portion 40 above, this is just an example, and the area can be selected depending on the purpose. Nor. The same applies to the number of non-magnetized portions 40 formed.

[Effects of the Invention] As described above, according to the present invention, the magnet 23 that functions as a frequency generator is used, the non-magnetized portion 40 is formed in a part of the magnet 23, and the detection coil 32 is A detection element 33 for detecting a PG signal is provided in a part.

According to this configuration, since the element for detecting the FG signal can be shared as the element for the PG signal, the unipolar magnet for PG (No. Since the detection element 33 can be arranged on the substrate 31, it is possible to downsize the rotation detection device and thereby reduce the cost.

Further, depending on the number of non-magnetized portions 40 formed, any PG
Since a multiplied signal can be obtained, it has many features such as being able to easily form a PG multiplied signal depending on the purpose.

Therefore, as described above, the present invention is extremely suitable for application to drive devices such as floppy desks and VTRs that require miniaturization and high reliability.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an example of a rotating device according to the present invention,
Fig. 2 is a block diagram of the rotating part used in this, Fig. 3 is a block diagram of the rotation detecting part, Fig. 4 is a partial sectional view thereof, and Fig. 5 is another example of the rotation detecting part. 6 is a waveform diagram for explaining rotation detection operation, FIG. 7 is a system diagram showing an example of the PG detection circuit, FIG. 8 is a waveform diagram showing an example of the system diagram operation, and FIG. 9 is a waveform diagram showing an example of the system diagram operation. 10 is a configuration diagram showing another example of the rotation detection section, FIG. 10 is a waveform diagram for explaining the detection operation, and FIG.
1 is another configuration diagram of the rotating section, FIG. 12 is a configuration diagram of the rotation detection section at that time, and FIG. 13 is an explanatory diagram of the detection signal.
FIG. 14 is a block diagram of a conventional rotating device, FIG. 15 is a block diagram of a rotating section, FIG. 16 is a block diagram of a rotation detecting section used therein, and FIG. 17 is an explanatory diagram of a detection signal. 10... Rotating device 1... Motor 20... Rotating part 23... Magnet 30... Rotation detecting part 32... Detecting coil 32b... Comb tooth coil 33... Detecting element 40. 41...Non-magnetized part a...FG double signal...PG double signal Applicant Nippon Chemi-Con Co., Ltd. Figure 1 10: ! ] #5l-L1? p Fig. 2 Sake; (51 Hayashi Kano Fig. 3 Fig. 4 Fig. 5 Fig. 6 Fig. 8 Fig. 9 ・A-so S No. d) \ko/()\yu/--- ---,
tZZ ( ) The l cap is the 15th star

Claims (1)

[Scope of Claims] (1) Consisting of a rotating part connected to a rotating shaft of a rotating device, and a rotation detecting part disposed facing the rotating part with a predetermined gap therebetween, the rotating part has a plurality of rotating parts. The rotation detecting section includes a comb-shaped detection coil that detects the magnetized section of the magnet. and a detection element for detecting the non-magnetized portion. (2) The rotating device according to claim 1, wherein the rotating section and the detection coil constitute a frequency generator. (3) Claim 1, characterized in that a pulse signal generator is constituted by the rotating section and the detecting element.
Rotating device as described in section.