JPH08261245A - Torque transmission mechanism - Google Patents

Abstract

PURPOSE: To provide a torque transmission mechanism whose maximum transmission torque is large and inertia mass is small under a low speed rotation state in order to realize a rotation drive mechanism with a low vibration and a quick start up. CONSTITUTION: In a torque transmission mechanism in which an input side torque plate 22 and an output side torque plate 23 applied a multipole magnetization are arranged coaxially with some clearances and a rotational torque is inputted from an input rotary shaft 21 and a torque is transmitted to an output rotary shaft 24, a centrifugal brake 25 constituted by a flexible material fixed on the output rotary shaft 24, whose at least one part of thickness is the same as the clearance is arranged.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary torque transmission mechanism for an electric machine.

[0002]

2. Description of the Related Art Conventionally, the measurement of the floating clearance of a magnetic head,
In the measurement of the frictional force of the medium disk and the contact start / stop life test, only the physical characteristics are accurately measured, so that the vibration of the rotating body is required to be as small as possible. It has been known to use an air bearing for floatingly supporting a rotary shaft by air pressure for a rotary spindle in order to realize rotary drive with less vibration. Generally, balls or cylinders made of metal or the like are used between the rotating cylinder part and the fixed cylinder part, and ball bearings of the type that realize rotation with less friction by the rotation are widely used, but this type of bearing is Although it is inexpensive and easy to handle, it has the drawback of generating minute vibrations called ball passing vibrations when the ball rotates. It is known that the air bearing has very little vibration because there is no such sphere between the rotating portion and the fixed portion. However, in order to actually configure the rotary drive mechanism, it is necessary to combine such a bearing and a motor that generates a driving force, but normally, an electric motor uses a ball bearing for its rotary shaft, and If the air bearing is rigidly coupled, not only the vibration of the electric motor but also the vibration of the ball bearing used for the bearing of the motor is transmitted, and the advantage of using the air bearing is lost. Therefore, it has been customary to use a magnetic coupler (magnet coupler) capable of transmitting rotational torque in a non-contact manner for coupling the electric motor and the air bearing.

The magnet coupler is arranged such that the disks of the permanent magnets are opposed to each other, and only the force in the direction of the rotation axis is transmitted by utilizing the magnetic coupling force that attracts the N and S poles of the magnetic poles.
It is well known that the stronger the permanent magnet and the larger the disc diameter, the larger the binding force and, consequently, the maximum torque that can be transmitted. The strength of the permanent magnet is roughly determined by the material. It is about 40 MGOe. Therefore, in order to increase the maximum torque, it is necessary to increase the diameter of the disk. However, if this is done, the inertial mass will increase and the rise at startup will deteriorate.

[0004]

SUMMARY OF THE INVENTION The present invention solves the drawbacks of the conventional magnetic coupler and realizes a rotary drive mechanism with low vibration and quick start-up, so that the maximum transmission torque in a low speed rotation state is large, and An object is to provide a torque transmission mechanism having a small inertial mass.

[0005]

In order to achieve the above object, the torque transmission mechanism of the present invention has two discs, which are magnetized in multiple poles, arranged coaxially with a clearance provided therebetween. In a torque transmission mechanism that inputs rotational torque from one of the central shafts and transmits the torque to the other central shaft, it is fixed to the output side central shaft and at least part of its thickness is equal to the above clearance. It is characterized by arranging discs made of material.The maximum transmission torque in a low speed rotation state is large and the inertial mass is small, so to realize a rotary drive mechanism with low vibration and quick start-up. You can

[0006]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 shows an example of a rotary drive device using a torque transmission mechanism according to the present invention. 1 is an electric motor, 2 is a torque transmission mechanism, 3 is a hydrostatic bearing, 4 is a spindle hub, 5 is a disc, and 6 is a disc. Is a moving table, and 7 is a magnetic head. The fixed parts such as the case and the surface plate that support them are not shown in the figure. In the example of FIG. 1, the rotational torque generated by passing a current through the electric motor 1 is transmitted to the hydrostatic bearing 3 via the torque transmission mechanism 2 and rotates the spindle hub 4 to which the disc 5 is rigidly attached. The magnetic head 7 is fixed to the moving table 6 and can move in the radial direction of rotation of the disk 5, but is not connected to the disk 5 and contacts the surface of the disk 5 when the disk 5 is stopped. You can do it. In such a test device, for example, contact start / stop (Contact-Star
When performing a t-Stop) test, the disk 5 must be rapidly raised from a stopped state to a predetermined rotation speed. For this reason,
The torque transmission mechanism 2 needs to accurately transmit only the rotation torque of the motor 1 to the hydrostatic bearing 3 side. As is well known, the torque of the electric motor 1 is the largest at the time of starting, and becomes smaller as the number of rotations increases. Therefore, the maximum transmission capacity of the torque transmission mechanism 2 must prevent slipping even when the rotation is just started. is there.

FIG. 2 is an example of a sectional view of the torque transmission mechanism 2 according to the present invention. The left half of the drawing shows a stationary state (or a low speed rotation state) and the right half shows a high speed rotation state. In the figure,
Reference numeral 21 is an input rotary shaft, 22 is an input side torque plate, 23 is an output side torque plate, 24 is an output rotary shaft, and 25 is a centrifugal brake. The input side torque plate 22 and the output side torque plate 23 are both composed of permanent magnets magnetized in multiple poles, and face each other to form a magnetic coupler. When the two torque plates are opposed to each other, the N pole and the S pole attract each other and are rigidly coupled via the magnetic attraction force B, and the distance therebetween is set mechanically. When the motor 1 vibrates, the gap slightly changes. However, by setting the gap smaller than the magnetizing distance of the magnetic poles, the attraction force B hardly changes, so the vibration is not transmitted to the output side. The centrifugal brake 25 is a disk-shaped one made of a wear resistant flexible material such as rubber, and its central portion is connected to the output side torque plate 23.

In the stationary state, the input / output side torque plates 22, 2
The centrifugal brake 25 is arranged in the gap 3 and the torque from the input rotary shaft 21 at the time of start-up is transmitted through the frictional force of the centrifugal brake 25 together with the magnetic coupling force of the input / output side torque plates 22 and 23. Be transmitted to.

Centrifugal brake 2 with increasing rotational speed
The centrifugal force A acts on 5 so that the disk is stretched and the thickness of the centrifugal brake 25 is reduced, so that the disk is separated from the input side torque plate 22. As a result, the torque transmission mechanism of this embodiment operates exactly the same as a conventional magnet coupler at high speed rotation, and does not transmit vibration of the electric motor 1 or ball passing vibration of a ball bearing on the side of the electric motor 1 and a rotational torque. Can only communicate. Since the frictional force of the centrifugal brake 25 transmits the torque at the time of start-up as described above, the input / output side torque plates 22 and 23 can be made small enough to transmit the required torque at high speed rotation. With the mechanism, the inertial mass can be dramatically reduced, and since the flexible centrifugal brake 25 absorbs the vibration of the motor 1 at the time of starting, the starting vibration is also greater than when using a huge McNet coupler capable of transmitting the starting torque. Can be made smaller. Also, because the expensive magnet can be made smaller,
It is also an advantage of this embodiment that the cost can be reduced.

FIG. 3 shows another example of the present invention. The input side torque plate 22 'having an extremely low conical surface and the output side are arranged so that the gap in the central portion becomes narrower than the outer edge portion when facing each other. A torque plate 23 'is used. As a result, the centrifugal brake 25 '
By forming the contact part of the conical shape with the conical shape of the input side torque plate 22 'and the output side torque plate 23', the detachment of the centrifugal brake 25 'becomes clearer when the rotational speed increases, and when the brake is pressure-bonded. The frictional force of can be increased. In this example, since the pressure-bonded portion of the centrifugal brake 25 'also has an inverted conical shape, the braking area can be made clear, and the design for obtaining a predetermined frictional force is also easy. Further, there is also an advantage that it is possible to change the number of rotations to be separated by adjusting the gap by changing the gap.

[0012]

As described above, according to the present invention, torque can be transmitted by using the frictional force of the centrifugal brake even if the diameter of the McNnet coupler is made small. Therefore, the size is small, the inertial mass is small, and the start-up is small. There is an advantage that a torque transmission mechanism having a large transmission torque can be realized at low cost.

[Brief description of drawings]

FIG. 1 is a perspective view showing an example of a rotation drive device using a torque transmission mechanism according to the present invention.

FIG. 2 is a structural cross-sectional view showing an example of a torque transmission mechanism according to the present invention.

FIG. 3 is a configuration cross-sectional view showing another example of the torque transmission mechanism according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electric motor, 2 ... Torque transmission mechanism, 3 ... Hydrostatic bearing, 4 ... Spindle hub, 5 ... Disc, 6 ... Moving stand, 7 ...
Magnetic head, 21 ... Input rotating shaft, 22 ... Input side torque plate, 23 ... Output side torque plate, 24 ... Output rotating shaft, 25 ...
Centrifugal brake.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shinji Hara 1-1-6 Uchisaiwai-cho, Chiyoda-ku, Tokyo Nihon Telegraph and Telephone Corporation (72) Reizo Kaneko 1-1-1-1 Uchiyuki-cho, Chiyoda-ku, Tokyo No. 6 Nihon Telegraph and Telephone Corp. (72) Inventor Makoto Asakawa 3-9-11 Midoricho, Musashino-shi, Tokyo Afti Co., Ltd.

Claims (1)

[Claims] 1. Two circular plates, which have been subjected to multi-pole magnetization, are arranged coaxially with a clearance, and a rotational torque is input from one of the respective central axes and the torque is transmitted to the other central axis. In the torque transmission mechanism, there is provided a disc which is fixed to the output side central shaft and is made of a flexible material, at least a part of which has a thickness equal to the above-mentioned clearance.