JPH08275449A - Driving apparatus - Google Patents

Abstract

PURPOSE: To enable adjustment of a tension of a long-length material by introducing a structure that the position of rotor in the radius direction can be controlled by feeding an electrical power to a coil for generating a force in the radius direction depending on a tension of the long-length material detected by a rotating position detector. CONSTITUTION: At the center of a driving apparatus 1, a stator 2 is provided as an armature and both torque generating coil and radius direction force generating coil are wound thereto, and moreover a rotor 3 of a permanent magnet magnetized in the number of poles equal to the number of poles for torque generation coil is also arranged to surround the stator 2. Moreover, at the external side of the rotor 3, a cylindrical rotor 4 is arranged in integration with the permanent magnet and is rotably supported by inserting a center shaft 7 into the center aperture of the disk type base 5 provided at the lower end via a bearing 6. When the power is supplied to the radius direction force generating coil loaded to the stator 2, a radius direction force is actively generated, enabling the rotor to be displaced in the radius direction. As a result, the tension is controlled to the minimum value for preventing looseness of the long-length material wound around the rotor.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device,
More specifically, VTR, tape recorder, 8mm deck,
It is applicable to small magnetic recording devices such as digital audio tape recorders (DAT) and cassette streamers, to large sheet winding devices for the steel industry, and drives that have a structure for revolving a sheet-like long object in a rotating body. Regarding the device.

[0002]

2. Description of the Related Art VTR,
For magnetic head devices in audiovisual products such as DAT and large-scale winding devices for metal sheets in the metal industry, it is required to realize tension control with higher accuracy.

Particularly, in a magnetic head device such as a VTR, since the magnetic tape wound around the magnetic head is constantly slipping without synchronizing with the rotation of the magnetic head, the relative speed between the magnetic tape and the magnetic head. The frictional force always fluctuates due to the fluctuation of the load. In addition, since it is essential to improve the recording density in order to improve the image quality, it is necessary to keep the gap between the magnetic tape and the magnetic head constant.

In order to meet this need, tension control of a magnetic tape which is held by a magnetic head is performed. However, since the magnetic tape itself is elastic, the distribution density of the magnetic material, and further the magnetic flux density, changes as the elongation of the magnetic tape changes due to tension. As a result, even if the tension of the magnetic tape is controlled,
It is difficult to realize a higher recording density.

On the other hand, in the metal industry, a thin metal plate is manufactured by rolling, which is wound into a coil and shipped. The rolling accuracy of a thin metal sheet is closely related to the quality and the market price, and highly accurate tension control is required in the final winding coil.

However, since the winding coil becomes thicker as the thin metal plate is wound up, it is not always possible to realize highly accurate tension control depending on the thickness accuracy of the thin metal plate, which is often difficult. It was

The present invention has been completed based on the above circumstances. That is, the object of the present invention is to reduce the tension of a long object such as a tape or a thin metal sheet which is rotated by the rotor by changing the radial position of the rotor in the outer rotor rotating mechanism. To provide a drive device.

[0008]

The present invention for solving the above-mentioned problems includes an outer rotor mechanism including a rotor, a rotor, a stator, and rotor position detecting means, wherein the rotor is , The rotor is rotatably arranged so as to surround the stator, the rotor is formed so that a long object can be rotated, and the rotor has an axis common to the axis of the rotor. The stator is coupled to the stator, and the stator has a number of poles different from those of the torque generating winding for generating torque in the cylindrical rotor and a radial direction of generating a radial force. A rotor for detecting the position of the rotor, the rotor position detecting means being capable of detecting the position of the rotor that changes according to the revolving state of the long object. For generating the radial force according to the tension of the long object A drive device, characterized by comprising enabling control the radial position of the rotor by energizing the line.

[0009]

Since the drive device of the present invention has the above-described structure, it detects the revolving state of a long object to be revolved by detecting the position of the rotor, and generates a radial force according to the relieving state. By energizing the winding, a radial force is generated in the rotor to adjust the tension of the long object to a predetermined tension.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the drive unit 1 is a radial biaxial control drive unit and has a structure suitable for a magnetic head drive unit of a VTR.

The drive device 1 has an outer rotor rotating mechanism. A stator 2 which is also an armature is provided in the center, and two kinds of windings are wound around the stator 2.
One of the windings is a torque generating winding (also called an electric motor winding) for operating as an electric motor, and the other winding is a radial force generating winding for generating a radial force. Is. The torque generating winding and the radial force generating winding have different numbers of poles. For example, if the torque generating winding has four poles, the radial force generating winding has two poles. In the present invention, the number N of poles of the torque generating winding and the number n of poles of the radial force generating winding have a relationship of N = n ± 2.

Surrounding the stator 2 is a rotor 3 which is a ring-shaped permanent magnet magnetized to have the same number of poles as the number of windings for torque generation.

For example, for the rotor 3 which is a four-pole ring-shaped permanent magnet, the stator 2 has a winding for torque generation and a radial force generation so as to generate a magnetic flux as shown in FIG. The winding is twisted. In FIG. 2, N ₂ , S ₂
Shows the magnetic pole by the two-pole winding wound around the stator, and N ₄ , S ₄ shows the magnetic pole by the two-pole winding wound around the stator by N _p and S _p . Shown are the magnetic poles of the rotor-side permanent magnet. N _4, S ₄ the rotational force (torque) generated by the radial forces generated by the N _2, S _2.

As shown in FIG. 1, a cylindrical rotating body 4 (also referred to as a yoke) is arranged outside the rotor 3 of the permanent magnet integrally with the permanent magnet.

The rotating body 4 is formed by inserting a central shaft 7 for fixing the stator 2 through a bearing 6 into a central opening of a disk-shaped base 5 provided at the lower end of the rotating body 4.
It is rotatably supported by the central shaft 7. Therefore, the upper end of the rotating body 4 is allowed to swing in the radial direction, for example, a precession movement. For example, as shown in FIG. 3, a bearing 6 that rotatably supports the central shaft 7 serves as a swing support point 8, and the central shaft can swing in the F _x direction and the F _y direction.

When the drive device 1 is a VTR magnetic head drive device, a magnetic head is mounted on the outer side of the rotating body 4.

By energizing the radial force generating windings mounted on the stator 2, a radial force is actively generated and the rotor can be displaced in the radial direction. Due to the radial displacement of the rotor, the rotor 4 of the drive device 1 is
It is possible to control the tension of long objects that rotate.

In FIG. 1, the torque generating winding has three phases and the radial force generating winding also has three phases.
It may be a phase winding.

These windings are connected to an inverter composed of transistors, FETs and the like. In the drive device 1 shown in FIG. 1, the torque generating winding is connected to the three-phase inverter 9, and the radial force generating winding is connected to the three-phase inverter 10.

In the drive device having the above structure, it is possible to generate the radial force by active feedback or feedforward. If the radial position is detected and fed back, the radial position can be actively controlled to perform highly accurate tension control.

When this drive device is a head drive device, as shown in FIG. 4, a long magnetic tape 12 is wound around the outer periphery of the magnetic head 11. In the head drive device, the magnetic head 11 is mounted on the rotating body 4 shown in FIG. 1, or the rotating body 4 itself is used as the magnetic head 11.

In the head drive device, the magnetic information read by the head, for example, a carrier tracking signal is inputted and a judging means for judging which portion between the tape and the head has a gap, and this judging means is outputted. PI or PID control means for inputting the determination signal and outputting a control signal for controlling the current output from the inverter is provided. This determining means determines whether the virtual center axis of the rotor is instantaneously displaced from the axis of the stator or the amount of deviation between the center axis of the stator and the center axis of the rotor changes. Since the gap between the tape and the head, which occurs due to the change in tension, is detected, this determination means corresponds to the rotor position detection means in this invention.

When the drive device is a drive device other than the head drive device, as the rotor position detecting means, a well-known detecting means such as a position detecting means using an optical means such as a gap sensor or a laser is adopted. can do.

Therefore, according to the head drive device incorporating this drive device, the running state of the tape on the head is determined, and for example, when a gap is formed between the head and the tape, the inverter is immediately connected to the radial force generating winding from the inverter. When a predetermined current is applied, a radial force that eliminates the gap is generated, and the running state of the tape on the head is maintained optimally.

FIG. 5 shows a drive device according to another embodiment of the present invention.

The drive device 21 shown in FIG. 5 is a drive device of radial four-axis control. The drive device 21 shown in FIG. 5 has an outer rotor rotating mechanism and can control the rotor 23 in four radial directions. That is, the radial direction biaxial rotational force Fx on the upper portion of the rotor 23.
₂ , Fy ₂ and the radial biaxial radial force Fx _{1 of} the lower part,
Are configured to generate Fy ₁ . That is, the stator 22 is divided into an upper stator 22a and a lower stator 22b. The upper stator 22a and the lower stator 22b are mounted on a single central shaft 27.

As shown in FIG. 6, the upper stator 22a
Radial force generating winding 22c is倦回the independent radial force generating winding and倦回by radial force generating winding 22 c in the upper stator 22a is the lower stator 22b Two
Each 2d is relieved. Further, a common torque generating winding is wound 22e between the upper stator 22a and the lower stator 22b.

Therefore, in the radial four-axis control drive device, six radial phase force generating windings are required if they are three-phase windings for controlling up and down, and these are connected to an inverter. The current is controlled according to the required radial force.

A magnetic bearing 28 is provided below the central shaft 27, and the stator 22 is magnetically levitated and supported thereby. When the stator 22 is magnetically levitated via the central shaft 27, the central shaft, which is the rotating shaft, has no mechanical contact portion, and thus high-speed rotation without vibration or noise can be easily realized, which is advantageous. Further, a position detector (not shown) is also provided on the magnetic bearing 28, and the displacement of the central shaft 27 can be detected by the position detector.
The displacement of the rotor 23 can be relatively detected by detecting the displacement. 24
Indicated by is a rotating body.

[0031]

[Effect] The drive device of the present invention is capable of rotating a long object in a rotating body in a small magnetic recording device such as a VTR, a tape recorder, an 8 mm deck, a DAT, a cassette streamer or a large sheet winding device for the steel industry. It can be applied to a drive device having the above structure.

The drive device according to the present invention can control the minimum tension as necessary, that is, without applying an excessive tension to prevent loosening of a long object that is rotated around the rotating body. .

Since the torque generating winding and the radial force generating winding are wound around and integrated with the same stator, the torque generating winding and the radial force generating winding are arranged like a magnetic bearing. The leakage portion of the magnetic flux is smaller than that of a device in which the wire and the wire are wound around separate stators, and therefore, the leakage magnetic flux can be easily sealed, thereby reducing loss.
Moreover, the device configuration can be made compact.

Compared with the method of controlling the tension of a long object by torque control, the center of the rotating shaft of the rotating body can be displaced minutely, so that the surface of the magnetic head is always slid as in a magnetic head drive device, for example. Even with a device such as a magnetic tape having large fluctuations in friction, tension control can be easily performed.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional explanatory view showing a drive device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram showing a state of magnetic flux formed in a rotor and a stator in a drive device according to an embodiment of the present invention.

FIG. 3 is an explanatory view showing a swinging direction of a stator, which is similar to the drive device according to the position embodiment of the present invention.

FIG. 4 is an explanatory diagram showing a state in which a magnetic tape is wound around a magnetic head in a magnetic head drive device incorporating a drive device according to an embodiment of the present invention.

FIG. 5 is a partial cross-sectional explanatory view showing a drive device according to another embodiment of the present invention.

FIG. 6 is a schematic explanatory view showing a torque generating winding and a radial force generating winding that are rotated around a stator and a rotor in a drive device according to another embodiment of the present invention. is there.

[Explanation of symbols]

1 ... Drive device, 2 ... Stator, 3 ... Rotor, 4 ... Rotating body, 5 ... Base, 6 ... Bearing, 7 ... Central axis, 8 ...・ Center of swing, 9 ・ ・ ・ 3
Phase inverter, 10 ... 3-phase inverter, 11 ...
Magnetic head, 12 ... Magnetic tape, 21 ... Drive device, 22 ... Stator, 22a ... Upper stator,
22b ... Lower stator, 22c, 22d ... Radial force generating winding, 22d ... Torque generating winding, 23
... Rotor, 24 ... Stator, 27 ... Center axis,
28 ... Magnetic bearing.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (71) Applicant 000226242 Nikkiso Co., Ltd. 3-43-2, Ebisu, Shibuya-ku, Tokyo (71) Applicant 000000239 Ebara Corporation 11-11 Haneda-Asahi-cho, Ota-ku, Tokyo (71) ) Applicant 000107996 Seiko Seiki Co., Ltd. 4-3-1 Yashiki, Narashino City, Chiba Prefecture (72) Inventor Akira Chiba 1-8-14 Shimochiai, Shinjuku-ku, Tokyo Ochiai Mansion 707 (72) Inventor Masa Fukao Yokohama, Kanagawa Prefecture 24-45 Matsufudai, Aoba-ku, Aichi (72) Inventor Riki Michioka 2-8-21 Hatanodai, Shinagawa-ku, Tokyo Heights Hatanodai 909

Claims (1)

[Claims] 1. An outer rotor mechanism comprising a rotor, a rotor, a stator, and rotor position detecting means, wherein the rotor is rotatably arranged so as to surround the stator, The rotating body is formed so as to be able to rotate a long object, and is coupled to the rotor so as to have an axis common to the axis of the rotor body, and the stator is attached to the cylindrical rotor. The torque generation winding for generating torque and the torque generation winding are different in the number of poles, and are provided with a radial force generation winding for generating a radial force. , For generating the radial force according to the tension of the long object detected by the rotor position detecting means, the position of the rotor changing according to the revolving state of the long object. If the radial position of the rotor is controlled by energizing the winding, Both are drive devices characterized in that the rotor can be magnetically supported in the radial direction.