JPH0311022B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is applicable to a drive device for a floppy desk,
The present invention relates to a rotating device suitable for application to 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. The system 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.

The rotating part 20 has an inward flange 2 as shown in the figure.
2, 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 includes a detection coil 32 formed on a predetermined mounting board 31 (fixed to a motor mounting member). To,
It is provided in a comb-teeth shape so as to face the magnet 23 with respect to the mounting board 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 arranged on the outer peripheral surface of the mounting board 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 2
4 and the detection element 33 constitute a pulse generator.

Therefore, by driving the motor 1, the output terminal 32a of the detection coil 32 has the voltage shown in FIG.
As shown in Figure B, a sinusoidal detection signal a (FG signal) is detected, and the output terminal 33a of the detection element 33 receives a pulsed detection signal b as shown in Figure
(PG signal) is obtained. It goes without saying that the rotational speed of the motor can be detected by the FG signal, and the rotational phase of the motor can be detected by the PG signal.

[Problems to be solved by the invention] By the way, the rotating device 10 configured as described above
Now, in order to detect the PG signal, as mentioned above, in addition to the FG signal detection means, the unipolar magnet 24,
A detection element 33 must be provided.

Therefore, since these elements are arranged on the rotating disk 21 and the mounting board 31, it is not only a bottleneck in downsizing the rotation detection device itself, but also an increase in cost due to an increase in the number of detection parts. It's summery.

Therefore, the present invention proposes a rotating device that solves these conventional problems with a simple structure and that is small 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 in that it is provided with a detection coil formed in a comb-tooth shape for detecting a magnetized portion of the magnet, and a detection element for detecting a non-magnetized portion.

[Operation] 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) that is in the same state as if the non-magnetized part was also magnetized, that is, the FG signal. can get. 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, thereby making it possible to easily and reliably detect the rotational phase of the motor.

[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 10 according to the present invention, and this rotating device 10 also has a rotating section 20 attached to a rotating shaft 2 of a motor 1.
and a rotation detecting section 30 arranged to face this.

The rotating part 20 includes a rotating disk 21 and a rotating disk 2.
1 and a magnet 23 attached on top of the magnet 23.

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 a part of the magnet 23 has a non-magnetized portion. 40 are provided.

In the non-magnetized portion 40, a portion corresponding to one to several magnetic poles is 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 detection section 30 includes a detection coil 32 and a detection element 3 formed on the lower surface of the mounting board 31 by printing or the like.
It consists of 3.

That is, as shown in FIG.
As in the conventional case, the coils 2 are formed in a comb-teeth shape in the circumferential direction, and the number of comb-teeth coils 32b is set to about half the number of magnetic poles of the magnet 23, for example.

A detection element 33 is formed in a part of this detection coil 32. The detection element 33 may be a simple coil, a magnetic head, or a Hall element (Hall IC).
), a magnetoresistive element, etc. can be used.

What is shown in FIG. 3 is a case where coils are used, and one comb-tooth coil 32b of the detection coil 32 is used.
Only one turn is formed in the vicinity of , 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 of FIG. 3, and both A and B of the same figure show the case where the detection element 33 is formed on the same plane as the detection coil 32.

In the case of A in the same figure, an insulating layer 36 such as SiO ₂ is provided on the upper surface of the detection coil 32 printed and wired, and the detection element 33 is placed at a predetermined position on the upper surface, in this example, directly above the detection coil 32. The constituent coils are printed.

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.

As shown in FIG. 5, the detection element 33 can also be formed on the surface of the mounting substrate 31 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 4 of the rotating section 20 constitutes a frequency generator.
0 and the detection element 33 of the rotation detection section 30 constitute 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 time T.

Therefore, at both terminals 32a of the detection coil 32,
A sinusoidal detection signal a shown in FIG. 3D is obtained.
This detection signal a is used as an FG signal.

Here, this detection signal a 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 will cross.

Therefore, the voltage induced in the comb-tooth coil facing the magnetic pole is integrated and output to the output terminal 32a, and as a result, even if the non-magnetized portion 40 exists in a part of the magnet 23, The detection signal a is 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, the detection element 33 is connected to the detection coil 32.
Since it is formed only to correspond to one comb-teeth coil 32b, there is no integral action like the detection coil 32, and the signals corresponding to the magnetized portion and non-magnetized portion 40 of the magnet 23 are It will be detected.

That is, as shown in FIG. 6E, the non-magnetized portion 4
Since no detection signal is obtained at the time when 0 passes through the detection element 33, the detection signal b becomes 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 b.

Now, from this discontinuous detection signal, 1 of motor 1
In order to form one pulse per rotation, that is, a PG signal, the above-mentioned continuous detection signal a and discontinuous detection signal b may be processed.

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 sent to a subtraction circuit 5 made up of a differential amplifier, etc.
1, and the detection signal b is supplied to a predetermined amplifier 5.
2 to one input terminal of the subtraction circuit 51, that is, the negative terminal.

As a result, since the detection signal a and the detection signal b 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, FIG.
As shown in FIG. 2, some signals are detected from the boundary portion of the non-magnetized portion 40 due to the influence of the adjacent magnetized portions.

Therefore, the subtraction 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 signal.

When a Hall element is used as the detection element 33, it is attached at a position as shown in FIG.

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

In addition, when only one magnetic pole formation position is selected as the non-magnetized portion 40, the detection operation is performed at the tenth position.
The result will be as shown in the figure. However, this is a case where a Hall element is used as the detection element 33. Since the detection operation is the same as that shown in FIG. 6, detailed explanation thereof 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, non-magnetized portions 40 and 41 are formed at positions facing each other at an angle of 180 degrees, corresponding to three magnetic poles in this example.

On the other hand, on the mounting board 31 side, there is a 12th
As shown in the figure, single coils 33b, 33 facing each other at 180 degrees constitute the detection element 33 with one turn each.
c 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 b obtained from the detecting element 33 corresponds to one rotation of the motor 1, as shown in FIG. 2 PG per
A signal (pulse) can now be obtained.

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

In the above description, a region corresponding to one or three magnetic poles is exemplified as the non-magnetized portion 40, but this is merely an example, and it goes without saying that the region can be selected depending on the purpose. Non-magnetized part 4
The same applies to the number of 0s 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, the FG signal detection element is
Since it can be shared as a signal element, there is no need for a single-pole magnet for PG signals, which reduces the number of parts and allows the detection element 33 to be mounted on the mounting board
Since it is possible to arrange the rotation detection device, it is possible to downsize the rotation detection device and further reduce costs.

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

Therefore, as mentioned above, this invention can be applied to floppy desks and other devices that require miniaturization and high reliability.
It is extremely suitable for application to drive devices such as VTRs.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an example of a rotating device according to the present invention, FIG. 2 is a configuration diagram of a rotating section used in this, FIG. 3 is a configuration diagram of a rotation detecting section, and FIG. 5 is a configuration diagram showing another example of the rotation detection section, FIG. 6 is a waveform diagram for explaining the rotation detection operation, and FIG. 7 is a system diagram showing an example of the PG detection circuit. Figure 8 is a waveform diagram showing an example of the system diagram operation, Figure 9 is a configuration diagram showing another example of the rotation detection section, Figure 10 is a waveform diagram explaining the detection operation, and Figure 11 is the rotation unit. Other configuration diagrams, FIG. 12 is a configuration diagram of the rotation detection section at that time, FIG. 13 is an explanatory diagram of the detection signal, FIG. 14 is a configuration diagram of a conventional rotating device, and FIG. 15 is a diagram of the rotation detection section. Fig. 16 is a block diagram of the rotation detecting section used in this, Fig. 17 is a block diagram of the rotation detection section used for this.
The figure is an explanatory diagram of a detection signal. 10... Rotating device, 1... Motor, 20... Rotating section, 23... Magnet, 30... Rotation detection section, 32
...Detection coil, 32b...Comb tooth coil, 33...
...Detection element, 40, 41...Non-magnetized part, a...
FG signal, d...PG signal.

Claims (1)

[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, the rotating part has a plurality of magnetic poles. is composed of a magnet magnetized and a non-magnetized part provided in a part of the magnet, and the rotation detection part includes a detection coil formed in a comb-like shape for detecting the magnetized part of the magnet; A rotating device comprising 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. The rotating device according to claim 1, wherein the rotating section and the detecting element constitute a pulse signal generator. 4. The rotating device according to claims 1 to 3, wherein the non-magnetized portion is selected to correspond to one to several magnetic poles.